(Plenty of security around, and a blonde woman instead of Uhura at communications.)
PALMER: The distress call definitely came from one of the solar systems in this sector.
KIRK: Can you pinpoint it any closer, Lieutenant?
PALMER: Negative. It was so badly garbled all we got was the name Constellation, then we lost it.
SULU: Sir, we're now within the limits of System L-370, but I can't seem to locate
SPOCK: Captain, sensors show this entire solar system has been destroyed. Nothing left but rubble and asteroids.
KIRK: But that's incredible. The star in this system is still intact. Only a nova could destroy like that.
SPOCK: Nonetheless, Captain, sensors show nothing but debris where we charted seven planets last year.
KIRK: Continue a search pattern.
SULU: Aye, aye, sir.
(Later.)
SULU: Entering limits of System L-374, sir. Scanners show the same evidence of destruction.
KIRK: Every solar system in this sector blasted to rubble and still no sign of the Constellation. Matt Decker's in command. What could have happened to him?
SPOCK: Captain, the two inner most planets of this system appear to be intact.
PALMER: Sir, I'm picking up a ship's disaster beacon.
KIRK: Try to raise it, Lieutenant.
SPOCK: I have it on the sensors, Captain. By configuration, a starship stopped in space. She appears to be drifting.
PALMER: No answer, Captain. All I get is the automatic beacon.
SPOCK: Sensors not recording normal energy output.
KIRK: Approach course, Mister Sulu.
(They arrive at a ship hanging crookedly in space. It looks identical to Enterprise.)
KIRK: It's the Constellation. Look at that.
SPOCK: She may have been wrecked by whatever destroyed these solar systems.
KIRK: She was attacked. Red alert! Red alert! Man your battle stations!
PALMER: Red alert. Red alert. Man your battle stations.
KIRK: Mister Sulu?
SULU: All phaser banks manned and ready, sir.
KIRK: Very good. Initiate a full sensor scan of the immediate area for any other vessel.
SULU: Aye, sir.
KIRK: Lieutenant Palmer.
PALMER: I can't raise the Constellation, sir. I'm still getting the distress beacon, but there's heavy subspace interference. It's almost blocking the signal.
KIRK: Keep trying. Mister Spock, full evaluation of the damage to the Constellation.
SPOCK: All power plants dead, reserve energy banks operative at a very low power level.
KIRK: Life support systems?
SPOCK: Also operative at a low power level. The entire Bridge is damaged and uninhabitable. The rest of the ship seems able to sustain life.
KIRK: Radiation levels?
SPOCK: Normal, but subspace interference makes readings difficult.
SULU: No other vessels in the area, Captain. All scanners show clear.
KIRK: All hands, go to Yellow Alert. Stand by battle stations. Lieutenant, have Doctor McCoy, Mister Scott, and a damage control party report to me in the transporter room.
PALMER: Aye, aye, sir.
KIRK: We're going to board her. Mister Spock, you're in command.
SPOCK: Acknowledged.

[Constellation corridor]

(The name ship for the Constellation-class is a mess, with chunks blown out of her nacelles and saucer. Inside, pipes are hanging down, twisted.)
WASHBURN: Radiation level normal. Atmospheric pressure eleven pounds per square inch.
CREWMAN: Filtration systems are out, sir.
SCOTT: The whole communication system looks to be shorted out, too, sir.
KIRK: Scotty, check the phaser banks. See if they've been fired. Bones, you come with me.
SCOTT: Come along, lads.
(They head down a ladder while McCoy and Kirk walk off.)

[Constellation Engineering]

WASHBURN: What a mess.

[Constellation Room]

KIRK: No clutter, no half-empty cups of coffee. Whatever happened didn't happen without a warning.

[Constellation Engineering]

WASHBURN: What do you think did it, sir?
SCOTT: I don't know, lad. But I want a full structural and control damage check, and I'm going to have a look at those engines.

[Constellation Room]

KIRK: The crew wasn't abducted, they just left. Kirk to Enterprise.
SPOCK [OC]: Enterprise, Spock here.
KIRK: No survivors, no bodies either.

[Bridge]

KIRK [OC]: Is it possible they could have beamed down to one of the two planets?
SPOCK: Improbable, Captain. The surface temperature of the inner planet is that of molten lead. The other has an atmosphere poisonous to human life.

[Constellation Room]

KIRK: We'll continue our search. Kirk out.

[Constellation Corridor]

(Scott returns to the beam-in point.)
SCOTT: Captain, I've checked the engines. The warp drive is a hopeless pile of junk. The impulse engines are not too badly off. We ought to be able to do something with them.
KIRK: Phaser banks?
SCOTT: Exhausted. They didn't give up without a battle.
KIRK: But where are they? I can't imagine a man like Matt Decker abandoning ship while his life support systems were still operative.
SCOTT: Computer system is still intact. We can playback the duplicate Captain's Log from the auxiliary control room.
(They head off, then Kirk spots a man at a desk in a room.)

[Constellation Auxiliary Control]

(The man is conscious but dazed, stunned.)
KIRK: Matt. Matt, it's Jim Kirk.
MCCOY: Commodore? Commodore Decker? (he injects him)
KIRK: Matt? Matt.
DECKER: Kirk. It's Jim Kirk.
KIRK: What happened to your ship, Matt?
DECKER: A ship. Attacked. That, that thing.
KIRK: What thing? What was it?
DECKER: That
KIRK: Answer me! What was it? What happened, Matt?
MCCOY: Jim, give him a minute. He's in a state of shock.
SCOTT: Ready with the duplicate log, sir.
KIRK: Go.
DECKER [OC]: Captain's log, stardate 4202.1. Exceptionally heavy subspace interference still prevents our contacting Starfleet to inform them of the destroyed solar systems we have encountered. We are now entering system L-374. Science Officer Masada reports the fourth planet seems to be breaking up. We are going to investigate.
KIRK: The fourth planet. Only two left now. Scotty, pull the microtapes from the sensor memory banks and beam them aboard to Spock. I want a full analysis, a complete report of what happened when they went in on that planet.
DECKER: We tried to contact Starfleet. No one heard. No one! We couldn't run.
KIRK: What happened to your crew?
DECKER: Oh, I had to beam them down. We were dead. No power, our phasers useless. I stayed behind, the last man. The Captain, the last man aboard the ship. That's what you're supposed to do, isn't it? And then it hit again and the transporter went out. They were down there, and I'm up here.
KIRK: What hit? What attacked you?
DECKER: They say there's no devil, Jim, but there is. Right out of hell, I saw it.
KIRK: Matt, where's your crew?
DECKER: On the third planet.
KIRK: There is no third planet.
DECKER: Don't you think I know that? There was, but not anymore. They called me. They begged me for help, four hundred of them. I couldn't. I couldn't. (breaks down in tears)
SCOTT: Captain, Washburn has our report.
KIRK: Go.
WASHBURN: We made a complete check on structural and control damage, sir. As far as we can tell, something crashed through the deflectors and knocked out the generators. Somehow the antimatter in the warp drive pods has been deactivated.
KIRK: Deactivated? Scotty, could some kind of general energy dampening field do that, and would the same type of thing account for the heavy subspace interference?
SCOTT: Aye, that all adds up. But what sort of a thing could do all that?
DECKER: If you'd seen it, you'd know. The whole thing's a weapon. It must be.
KIRK: What does it look like?
DECKER: Well, it's miles long, with a maw that could swallow a dozen starships. It destroys planets, chops them into rubble.
KIRK: What is it, an alien ship? Or is it alive, or is it
DECKER: Both or neither. I don't know.
KIRK: Matt, your log stated that the fourth planet was breaking up. You went in to investigate.
DECKER: We saw this thing hovering over the planet, slicing out chunks of it with a force beam.
KIRK: Did you run a scanner check on it? What kind of a beam?
DECKER: Pure antiproton. Absolutely pure.
KIRK: (answers communicator) Kirk here.
SPOCK [OC]: Spock here, Captain.

[Bridge]

SPOCK: Unable to raise Starfleet Command due to heavy subspace interference.

[Constellation Auxiliary Control]

SPOCK [OC]: Attempting to remedy.
KIRK: What about the Constellation's tapes?

[Bridge]

SPOCK: She was attacked by what appears to be essentially a robot, an automated weapon of immense size and power. Its apparent function is to smash planets to rubble and then digest the debris for fuel. It is, therefore, self-sustaining as long as there are planetary bodies for it to feed on.

[Constellation Auxiliary Control]

KIRK: A robot weapon that purposely destroys entire solar systems. Why?

[Bridge]

SPOCK: Unknown, Captain. However, Mister Sulu has computed the path of the machine, using the destroyed solar systems as a base course. Projecting back on our star charts, we find that it came from outside, from another galaxy.
KIRK [OC]: What is the projected course of this thing?
SPOCK: If it follows its present path, it will go through the most densely populated section of our galaxy.

[Constellation Auxiliary Control]

KIRK: Thank you. Stand by, Mister Spock. Kirk out.
MCCOY: This whole thing's incredible. A robot? A machine like that, who would build it?
KIRK: We don't know. An alien race, apparently from another galaxy.
MCCOY: But why?
KIRK: Bones, did you ever hear of a doomsday machine?
MCCOY: No. I'm a doctor, not a mechanic.
KIRK: It's a weapon built primarily as a bluff. It's never meant to be used. So strong, it could destroy both sides in a war. Something like the old H-Bomb was supposed to be. That's what I think this is. A doomsday machine that somebody used in a war uncounted years ago. They don't exist anymore, but the machine is still destroying.
DECKER: Oh, forget about your theories! That thing is on the way to the heart of our galaxy. What are you going to do about it?
KIRK: Take it easy.
MCCOY: The first thing we're going to do is get you back to the Enterprise.
DECKER: Oh, no, I stay here. I'm not leaving my ship!
KIRK: There's no ship to leave. It's a dead hulk! We'll take her in tow. I'll stay onboard and get her ready. You go back to the Enterprise with the doctor and let him help you.
DECKER: It's just that I, I, I never lost a command before.
KIRK: Kirk to Enterprise. Have the transporter room beam Doctor McCoy and Commodore Decker on board immediately.

[Transporter room]

(As Kyle beams them aboard, Spock's impassionate voice can be heard.)
SPOCK [OC]: Red alert! Red alert!
MCCOY: Come on.

[Bridge]

SPOCK: It came up on us fast, Captain, but we seem able to maintain our distance.
KIRK [OC]: We're blind here. What's it look like?
(Decker and McCoy enter. The viewscreen shows a thing with a big yellow maw, that tapers down along it's body to a pointed tail.)
SPOCK: It looks very much like Commodore Decker's planet killer. And it is pursuing us. (The viewscreen now shows it head-on. A round opening with a small sun partway down the gullet.)
SPOCK: We are more manoeuvrable, but it is gaining on us. Sensors indicate some kind of total conversion drive.

[Constellation Auxiliary Control]

SPOCK [OC]: No evidence of life, subspace interference level incredibly high.
KIRK: Whatever it is, we can't let it go beyond us to the next solar system. We have to stop it. If it's a robot, what are the chances of deactivating it?

[Bridge]

SPOCK: I would say none, Captain. The energy generated by our power nacelles seems to attracts it. I doubt we could manoeuvre close enough without drawing a direct attack upon ourselves.

[Constellation Auxiliary Control]

SPOCK [OC]: I also believe the nature of this machine precludes the possibility of easy access to its control mechanisms.

[Bridge]

SULU: It's closing on us, Mister Spock.
SPOCK: Closing, Captain.

[Constellation Auxiliary Control]

KIRK: All right. Lower your deflector screens Long enough to beam us aboard.
SPOCK [OC]: Acknowledged.

[Transporter room]

SPOCK [OC]: Transporter Room, stand by to beam landing party aboard.
KYLE: Ready to beam, sir.
(But the monster fires a ray at them, everyone goes flying and smoke comes out of a transporter pad.)

[Bridge]

SPOCK: Evasive action, Mister Sulu.
SULU: Aye, sir.
SPOCK: Damage report, all stations.
KYLE [OC]: Mister Spock, the transporter's out.
SPOCK: Affect repairs. Captain Kirk, come in please.
KIRK [OC]: Kirk here.
SPOCK: Captain, we've been attacked. The transporter is damaged. We're taking evasive action.
PALMER: Mister Spock, communication's damaged. We're unable to override interference.

[Constellation Auxiliary Control]

SPOCK [OC]: Damage in communications, Captain. Interference will (static)
KIRK: Spock? Spock? Come in, Spock. Spock? We're stuck, blind, and deaf.
SCOTT: And paralysed. No power.
KIRK: Well, we just can't stand around while our ship is being attacked. Scotty, you've got to get me some manoeuvering power.
SCOTT: I can't repair warp drive without a spacedock.
KIRK: Then get me impulse power. Half-speed, quarter-speed, anything. If we get this hulk moving, maybe we can do something.
SCOTT: Aye, the impulse engines are still in fair shape. I might coax them.
KIRK: Then get moving.
SCOTT: Come on, lad.
KIRK: Washburn, you get in there. Let's see what we can do about this viewing screen. I've got to find out what's happening out there.

[Bridge]

MCCOY: No casualties, Mister Spock. How are we doing?
SPOCK: We have outrun it, Doctor.
DECKER: Status report.
SPOCK: Impulse and warp engines operative, transporter and communications under repair. Random chance seems to have operated in our favour.
MCCOY: In plain, non-Vulcan English, we've been lucky.
SPOCK: I believe I said that, Doctor.
SULU: It's veering off, back on course for the next solar system. The Rigel colony, sir.
SPOCK: Evidently programmed to ignore anything as small as a ship beyond a certain radius. We'll maintain a discreet distance and circle back to pick up the Captain.
DECKER: You can't let that reach Rigel. Why, millions of innocent people would die.
SPOCK: I am aware of the Rigel system's population, Commodore, but we are only one ship. Our deflector shields are strained, our subspace transmitter is useless. Logically, our primary duty is to survive in order to warn Starfleet Command.
DECKER: Our primary duty is to maintain life and safety of Federation planets. Do you deny that?
SPOCK: Mister Sulu, you will lay in an evasive course back to the Constellation.
SULU: Aye, aye, sir.
DECKER: Belay that last order, helmsman. One hundred and eighty degree turn, hard about. We're going to attack.
(The whole Bridge holds its breath.)
SPOCK: You will carry out my last order, Mister Sulu.
DECKER: Mister Spock, I'm officially notifying you that I'm exercising my option under regulations as a Starfleet Commodore, and that I am assuming command of the Enterprise.
SPOCK: You have the right to do so, but I would advise against it.
DECKER: That thing must be destroyed.
SPOCK: You tried to destroy it once before, Commodore. The result was a wrecked ship and a dead crew.
DECKER: I made a mistake then. We were too far away. This time I'm going to hit it with full phasers at point-blank range.
SPOCK: Sensors show the object's hull is solid neutronium. A single ship cannot combat it.
DECKER: Mister Spock, that will be all. You have been relieved of command. Don't force me to relieve you of duty as well.
MCCOY: You can't let him do this, Spock.
DECKER: Doctor, you are out of line.
MCCOY: So are you, sir. Well, Spock?
SPOCK: Unfortunately, Starfleet Order 104, Section B, leaves me no alternative. Paragraph 1A clearly states
MCCOY: To blazes with regulations! You can't let him take command when you know he's wrong!
SPOCK: If you can certify Commodore Decker medically or psychologically unfit for command, I can relieve him under Section C.
MCCOY: I'll certify that right now.
SPOCK: You'll also be asked to produce your medical records to prove it.
MCCOY: Now, you know I haven't had time to run an examination on him.
SPOCK: Then your statement would not be considered valid.
DECKER: You may leave the Bridge, Doctor.
MCCOY: What about the Captain? We can't leave
DECKER: Doctor, you may leave the Bridge.
MCCOY: Spock, do something!
DECKER: Mister Spock knows his duty under regulations, Doctor. Do you? (McCoy leaves) Hard about, helmsman. Course thirty two degrees, mark ten. Deflectors at full power. Ready on main phaser banks.
SULU: Aye, aye, sir.
(Spock stands completely still, like a statue, as Enterprise arrives back at the planet-killer.)

[Constellation Auxiliary Control]

(Kirk is trying to mend the viewscreen, but just making smoke and spluttering noises.)
KIRK: Kirk here.

[Constellation Engineering]

SCOTT: Captain, the impulse engines' control circuits are fused solid.
KIRK [OC]: What about the warp drive control circuits?
SCOTT: Aye, we can cross-connect the controls, but it'll make the ship almost impossible for one man to handle.

[Constellation Auxiliary Control]

KIRK: You worry about your miracles, Scotty, I'll worry about mine. Get to work.

[Constellation Engineering]

SCOTT: Aye, sir.

[Constellation Auxiliary Control]

KIRK: Washburn, try the 2G6 circuit.

[Bridge]

SULU: Closing fast.
SPOCK: Deflector shields at full power. They can't take much more of this.
DECKER: Helmsman, hold your course. Stand by all phaser banks.
SULU: Aye, aye, sir.
(The planet killer fires at them.)
SPOCK: Deflectors holding, but weakening. We must retreat, Commodore. The energy drain
DECKER: I'm in command here, Mister Spock. Maintain your course, helmsman. Get us in closer.

[Constellation Auxiliary Control]

KIRK: Ready to give it a try?
WASHBURN: Just one minute, sir.
KIRK: Scotty, how you doing?

[Constellation Engineering]

SCOTT: Controls are all hooked up, sir. We should have some power for you soon.

[Constellation Auxiliary Control]

WASHBURN: Try it now, Captain.
KIRK: Yes, I think (an image of tiny Enterprise and the giant planet killer comes on screen) What the devil's going on?

[Bridge]

DECKER: Fire!
(Two phaser beams strafe the machine's body.)
SULU: Direct hit. It just bounced off.
SPOCK: Commodore, I urgently recommend immediate withdrawal.
DECKER: Recommendation noted. Maintain course. Fire!

[Constellation Auxiliary Control]

KIRK: Kirk to Enterprise. Come in. Enterprise, come in. Mister Spock, come in. Kirk to Enterprise. Scotty, where's that power?

[Constellation Engineering]

SCOTT: Coming, sir. If I push these impulse engines too hard in the condition they're in, they'll blow apart.

[Constellation Auxiliary Control]

KIRK: Washburn, get down to Engineering. Assist Mister Scott.
WASHBURN: Aye, sir. (leaves)
KIRK: Scotty, push it right to the edge. This ship has got to manoeuver.
SCOTT [OC]: Aye, sir.

[Bridge]

(Another blast from the machine.)
SPOCK; Sir, deflector shields are gone.
PALMER: (to Spock) Sir, Deck seven reports power failure in main energisers. Implementing emergency procedures. (another hit) Severe casualties reported on decks three and four. Damage control party sealing off inner hull rupture.
SPOCK: It has ceased fire. We're being held in a tractor beam. We're being pulled inside, Commodore. You must veer off.
DECKER: Maintain phaser fire, helmsman.
SPOCK: We have lost warp power. If we don't break the tractor beam within sixty seconds, we never will.
DECKER: But don't you understand? We've got to destroy it!
SPOCK: That, sir, is illogical. It is suicide. Attempted suicide would be proof that you are psychologically unfit for command. If you don't veer off, I shall relieve you on that basis.
DECKER: Veer off.
SPOCK: Emergency impulse power.
SULU: We can't break loose!
SPOCK; We need more power.
SULU: We haven't got it. We're being pulled inside.

[Constellation Auxiliary Control]

(Kirk sees Enterprise approach the planet-killer's 'mouth'.)
KIRK: Scotty, give me that power.

[Constellation Engineering]

SCOTT: You've got it, Captain. Just enough to move us. I can't do better.

[Constellation Auxiliary Control]

KIRK: That'll do. Full ahead, Mister Scott.
(A sudden jolt as Constellation overcomes inertia.)
KIRK: That's it, Mister Scott. Keep that power coming.

[Bridge]

DECKER: Full power astern.
SULU: Aye, sir. We still can't move.

[Constellation Auxiliary Control]

KIRK: Keep pouring it on, Scotty.

[Constellation Engineering]

SCOTT: Captain, I still don't know what we're doing.

[Constellation Auxiliary Control]

KIRK: We're moving, the Enterprise isn't. Maybe that thing will see us and let the Enterprise go. If I only had some phasers.

[Constellation Engineering]

SCOTT: Phasers? You've got 'em. I have one bank recharged.

[Constellation Auxiliary Control]

KIRK: Scotty, you've just earned your pay for the week. Stand by. Fire phasers.
(One beam lances out, and the monster turns.)

[Bridge]

SULU: We're loose, Commodore.
DECKER: Good boy, Jim. Between the two of us, we'll kill that thing.

[Constellation Auxiliary Control]

KIRK: Mister Scott, it worked. Great. (sees that maw turning towards them) I think it's great. Scotty, get us out of here.

[Bridge]

SPOCK: It's closing fast on the Constellation.
SULU: Standing by, sir.
SPOCK: Commodore, I suggest
DECKER: Kirk pulled us out of there by distracting it. Now it's our turn. Fire phasers. (they do) We did it! Hard about. Give me some distance.
SULU: We're moving away, Commodore.
SPOCK: This machine seems to have a programmed defensive sphere. Any energy source entering that field is subject to attack.
DECKER: Mister Spock, status report.
SPOCK: Warp drive and deflectors will be out for a solar day. Repairs proceeding on transporter and communications.
SULU: It's closing with us again, sir.
DECKER: Maintain speed and distance.
SULU: It's sucking in space rubble from those destroyed planets. Refueling itself.
SPOCK: We can maintain this speed for only seven hours before we exhaust our fuel, but it can refuel itself indefinitely.
DECKER: Then we'll have to fight it now before it gets any stronger.
SPOCK: Illogical. We cannot destroy it. Therefore, we cannot save Rigel. We must transport the Captain and the others from the Constellation and escape this thing's subspace interference in order to warn Starfleet Command.
PALMER: Mister Spock, we've pierced the interference locally.
SPOCK: Can you raise Starfleet?
PALMER: No, sir, but I've got ship-to-ship communications back. Picking up Captain Kirk.
SPOCK: On audio, Lieutenant.
KIRK [OC]: Enterprise. Enterprise, come in.
DECKER: Mister Spock, I am still in command. I will speak for this ship. Enterprise to Kirk.

[Constellation Auxiliary Control]

DECKER [OC]: Commodore Decker speaking.
KIRK: Matt. What's going on? Give me Mister Spock.

[Bridge]

DECKER: I'm in command here, Jim.
KIRK [OC]: What happened to Spock?
DECKER: Nothing. I assumed command according to regulations

[Constellation Auxiliary Control]

DECKER [OC]: Since your first officer was reluctant to take aggressive action against the
KIRK You mean you're the lunatic who's responsible for almost destroying my ship?

[Bridge]

DECKER: You are speaking to a senior officer, Kirk.
KIRK: Give me Spock.
DECKER: I told you, I am in command here, according to every rule in the book, Captain. Anything you have to say at all, you will say to me.

[Constellation Auxiliary Control]

KIRK: There's only one thing I want to say to you, Commodore. Get my ship out of there.

[Bridge]

KIRK [OC]: Mister Spock, ship status.
SPOCK: Commodore.
DECKER: Down here. (the arm of the Captain's chair)
SPOCK: Warp drive out. Deflector shields down. Transporter under repair. We are on emergency impulse power.

[Constellation Auxiliary Control]

KIRK: How long to repair warp drive?
SPOCK [OC]: At least one solar day.

[Bridge]

SPOCK: At our present rate of consumption, we'll exhaust our impulse power long before then.
SULU: It's gaining on us, sir.

[Constellation Auxiliary Control]

KIRK: Take evasive action, Mister Sulu.

[Bridge]

DECKER: I told you, I am in command here and I will give the orders, Captain. We're going to turn and attack.
KIRK [OC]: Not with my ship, you don't.

[Constellation Auxiliary Control]

KIRK: Mister Spock, relieve Commodore Decker immediately. That's a direct order.

[Bridge]

DECKER: You can't relieve me and you know it. According to regulations

[Constellation Auxiliary Control]

KIRK: Blast regulations! Mister Spock, I order you to assume command on my personal authority as Captain of the Enterprise.

[Bridge]

SPOCK: Commodore Decker, you are relieved of command.
DECKER: I don't recognise your authority to relieve me.
SPOCK: You may file a formal protest with Starfleet Command, assuming we survive to reach a Starbase. But you are relieved. Commodore. I do not wish to place you under arrest.
DECKER: You wouldn't dare. (Spock signals the guards forward) You're bluffing.
SPOCK: Vulcans never bluff.
DECKER: No. No, I don't suppose that they do. Very well, Mister Spock. The Bridge is yours.
SPOCK: Captain, I have assumed command.
KIRK [OC]: Good. Now, Mister Spock
SPOCK: One moment, sir. Commodore. I believe you are scheduled for medical examination. Mister Montgomery.
MONTGOMERY: Sir.
SPOCK: You will accompany the commodore to Sickbay.
MONTGOMERY: Aye, sir. Commodore?
(They leave.)
SPOCK: Mister Sulu, change course. Seven zero mark two one.
SULU: Mark twenty one, sir.
SPOCK: Captain, we are taking an evasive course back to you. We will try to stay ahead of the object until we can transport you aboard.

[Constellation Auxiliary Control]

KIRK: Fine. Just make sure you stay ahead of it.
(Back on the Enterprise, Decker fights Montgomery when they exit turbolift two. It takes a while, but eventually the red-shirt is knocked out and dragged into a side room. Decker then makes his way to the shuttlecraft hangar deck.)

[Constellation Auxiliary Control]

SCOTT [OC]: Captain Kirk.
KIRK: Yes, Scotty.

[Constellation Engineering]

SCOTT: I've hooked in ship's communication. The best I can give you on impulse is one third power. The shields are up but they won't last long.

[Constellation Auxiliary Control]

KIRK: Keep it going, Scotty, keep it going. Mister Spock.
SPOCK [OC]: Yes, sir.
KIRK: I'm plotting an intercept course. Will rendezvous with you at fourteen thirteen point seven hours.

[Bridge]

SULU: Mister Spock, someone's opening the shuttlecraft bay doors.
SPOCK: Shut them, Mister Sulu.
SULU: It's too late, sir.

[Constellation Auxiliary Control]

KIRK: Kirk to Enterprise. Why are you launching a shuttlecraft?

[Bridge]

SPOCK: Whoever it is, Captain, has no authorisation. Lieutenant, raise the shuttlecraft.
PALMER: Enterprise to shuttlecraft. Come in, shuttlecraft.

[Shuttlecraft]

PALMER [OC]: Enterprise to shuttlecraft. Come in, shuttlecraft. Come in, shuttlecraft.
DECKER: Shuttlecraft to Enterprise. Decker here.

[Bridge]

SPOCK: Commodore, I must insist that you return to the ship.

[Shuttlecraft]

DECKER: You said it yourself, Spock. There is no way to blast through the hull of that machine, so I'm going to take this thing right down its throat.

[Constellation Auxiliary Control]

KIRK: This is Kirk. Matt, you'll be killed.

[Shuttlecraft]

DECKER: I've been prepared for death ever since I, ever since I killed my crew.

[Constellation Auxiliary Control]

KIRK: No one expects you to die for an error in judgment.

[Shuttlecraft]

DECKER: The commander is responsible for the lives of his crew, and for their deaths. Well, I should have died with mine.

[Bridge]

SPOCK: You cannot succeed, Commodore. Your only logical alternative is to return to the ship.

[Constellation Auxiliary Control]

KIRK: Matt. Matt, listen to me. You can't throw your life away like this. Matt, you're a starship commander. That makes you a valuable commodity.

[Shuttlecraft]

KIRK [OC]: We need you, your experience, your judgment. Matt! (Decker turns off the intercom)

[Constellation Auxiliary Control]

KIRK: We're stronger with you than without you!
(The shuttlecraft enters the planet killer, and Decker dies in agony from the radiation.)

[Bridge]

SPOCK: He's gone. Constellation, come in, please.

[Constellation Auxiliary Control]

SPOCK [OC]: Captain Kirk, come in please.
KIRK: Kirk here.

[Bridge]

SPOCK: Sir, may I offer my condolences on the death of your friend. It is most regrettable.

[Constellation Auxiliary Control]

KIRK: It's regrettable that he died for nothing.

[Bridge]

SULU: Mister Spock, sensors indicate a minute drop in the machine's power emanations. Do you think the shuttlecraft explosion might have done some damage?
KIRK [OC]: What about that, Spock? Is it possible?
SPOCK: The drop in power is definite, Captain but negligible. The object is still pursing us, thereby causing us to drain our power reserve at a much greater rate.
PALMER: Mister Spock, the transporter is now operational.
SPOCK: Transporter operational, Captain. Shall we beam you aboard?

[Constellation Auxiliary Control]

KIRK: Negative.

[Bridge]

KIRK [OC]: Mister Scott and I will stay here, but beam the damage control party aboard.
SPOCK: There's little to be gained by staying aboard the Constellation.

[Constellation Auxiliary Control]

KIRK: Except possibly the destruction of that thing out there. Carry out your orders, Mister Spock.

[Bridge]

SPOCK: Acknowledged. Transporter Room. Beam damage control party aboard.
KYLE [OC]: Aye, aye, sir.

[Constellation Auxiliary Control]

KIRK: Spock, listen. Maybe Matt Decker didn't die for nothing. He had the right idea but not enough power to do it. Am I correct in assuming that a fusion explosion of ninety seven megatons will result if a starship impulse engine is overloaded?

[Bridge]

SPOCK: No, sir. Ninety seven point eight three five megatons.

[Constellation Auxiliary Control]

KIRK: Ninety seven point eight three five. Will it be powerful enough to destroy that thing out there?

[Bridge]

SPOCK: Negative, Captain. Its hull is pure neutronium. There is no known way of blasting through it.

[Constellation Auxiliary Control]

KIRK: Not through it, Spock, from inside it. Will it be enough?

[Bridge]

SPOCK: Insufficient data. I shall try to take further sensor readings.

[Constellation Auxiliary Control]

KIRK: Do the best you can and make it fast. Kirk to Scott.

[Constellation Engineering]

SCOTT: Here, sir. The damage control party just beamed back to the Enterprise.

[Constellation Auxiliary Control]

KIRK: Good. Scotty, can you set the ship's impulse engines to overload?

[Constellation Engineering]

SCOTT: Aye. The shape the thing's in, it's hard to keep her from blowing.

[Constellation Auxiliary Control]

KIRK I want you to rig a thirty second delay detonation device, and rig it so that it can be blown from up here.

[Constellation Engineering]

SCOTT: Aye, sir.

[Constellation Auxiliary Control]

KIRK: Set it and get up here as fast as you can.
SCOTT [OC]: Right away.
SPOCK [OC]: Captain?

[Bridge]

SPOCK: The object's neutronium hull makes sensor readings of the inner mechanism impossible.

[Constellation Auxiliary Control]

KIRK: Spock, you don't know?
SPOCK [OC]: Correct.

[Bridge]

SPOCK: Captain, you're getting dangerously close to the planet killer.

[Constellation Auxiliary Control]

KIRK: I intend to get a lot closer. I'm going to ram her right down that thing's throat.

[Bridge]

SPOCK: Jim, you'll be killed, just like Decker.

[Constellation Auxiliary Control]

KIRK: No. No, I don't intend to die, Mister Spock. We've rigged a delay detonation device. You'll have thirty seconds to beam me aboard the Enterprise before the Constellation's impulse engines blow.

[Bridge]

SPOCK: Your chances of survival are not promising. We don't even know if the explosion will be powerful enough.

[Constellation Auxiliary Control]

KIRK: A calculated risk, Mister Spock.
SPOCK [OC]: There's another factor, Captain. The transporter is not working at one hundred percent efficiency.

[Bridge]

SPOCK: Thirty seconds is very slim timing.

[Constellation Auxiliary Control]

KIRK: A chance I'll have to take. Kirk out.
SCOTT: A cranky transporter's a mighty finicky piece of machinery to be gambling your life on, sir.
KIRK: What about the detonator?
SCOTT: I've linked it in with the impulse control system. (flips a switch) It's armed now. Press this one. Thirty seconds later, poof! Once it's activated, there's no way to stop it.
KIRK: Understood. Mister Spock. Prepare to beam Scotty on board.
SPOCK [OC]: Transporter, stand by.
SCOTT: Good luck, Captain.
KIRK: Thank you.

[Transporter room]

(It takes longer than usual to materialise Mister Scott.)
SCOTT: What's the matter with that thing?
KYLE: It's a power drain somewhere, sir. I almost lost you.
SCOTT: It'll never work like this. It's the main junction circuitry. I'll get it.
KYLE: Bridge. Transporter malfunction.

[Bridge]

SPOCK: Transporter is out, Captain. You'll have to stand by.

[Constellation Auxiliary Control]

KIRK: I can't. Power level's dropping too fast. You'd better hurry.
SPOCK [OC]: Acknowledged.

[Jefferies tube]

(Amid spluttering cables)
SPOCK [OC]: Mister Scott, speed is of the essence.

[Bridge]

SULU: He's two thousand miles from the planet killer and closing fast.

[Jefferies tube]

(The cables stop spluttering.)
SCOTT: Bridge, transporter operational, but this jury-rigging won't last for long. He's got to come off now.

[Bridge]

SCOTT [OC]: I'll stand by here.
SULU: Fifteen hundred miles and closing.
SPOCK: Captain, transporter operational, but just barely.

[Constellation Auxiliary Control]

KIRK: Prepare to beam me aboard on my signal.

[Bridge]

SULU: One thousand miles and closing.
SPOCK: Transporter, stand by.
KYLE [OC]: Standing by, sir.
SULU: Five hundred miles and closing.

[Constellation Auxiliary Control]

(The throat of the machine fills the screen when he flips the final red switch.)
KIRK: Beam me aboard.

[Bridge]

SPOCK: Energise.

[Transporter room]

KYLE: Energising. Bridge, it's shorted out again.

[Jefferies tube]

SCOTT: Och, what's wrong with it?

[Constellation Auxiliary Control]

KIRK: Gentlemen, beam me aboard.
SPOCK [OC]: We can't, Captain. Transporter is out again.

[Bridge]

SPOCK: Mister Scott, twenty seconds to detonation.

[Jefferies tube]

SPOCK [OC]: Mister Scott?

[Bridge]

SPOCK: Mister Scott

[Jefferies tube]

SPOCK [OC]: Try inverse phasing.

[Bridge]

SULU: Sixty, fifty, forty

[Constellation Auxiliary Control]

SULU [OC]: Thirty.
KIRK: Gentlemen, I suggest you beam me aboard.

[Bridge]

SULU: Ten

[Constellation Auxiliary Control]

SULU [OC]: Nine, eight

[Jefferies tube]

SULU [OC]: Seven.
SPOCK [OC]: Mister Scott?
SCOTT: Try her now, Mister Kyle.
SULU [OC]: Six.

[Constellation Auxiliary Control]

SULU [OC]: Five, four
(We see the Constellation enter the planet-killer. We see Kyle frantically to beam something in. We see a cloud coming out of the planet-killer before there's a bang.)

[Transporter room]

KYLE: Bridge, we got him through!

[Bridge]

SPOCK: Energy output zero. Radiation level normal.
(Kirk runs in.)
SPOCK: Welcome aboard, Captain. Sensors show all energy sources deactivated. It's quite dead.
KIRK: Mister Sulu, ease us back to minimum headway. Conserve power as much as possible. Lieutenant Palmer, tell Mister Scott to expedite repairs on the warp drive. Poor Matt. He gave his life in an attempt to save others. Not the worst way to go.
SPOCK: Indeed, Captain. I presume your log will show that Commodore Decker died in the line of duty.
KIRK: Indeed it shall, Mister Spock. Ironic, isn't it? Way back in the 20th century, the H-Bomb was the ultimate weapon, their doomsday machine, and we used something like it to destroy another doomsday machine. Probably the first time such a weapon has ever been used for constructive purposes.
SPOCK: Appropriate, Captain. However, I can't help wondering if there are any more of those weapons wandering around the universe.
KIRK: Well, I certainly hope not. I found one quite sufficient.