"The Enterprise Mutiny"
Mr. Scott soon beeps Spock's communicator to tell him that an urgent message has come in from Starfleet, and that he is unable to reach the captain. Spock and his group begin searching for Kirk, and are able to track him using the impulses coming from his communicator.
They come to the top of a rocky outcrop and find Kirk laying unconscious on the ground - with a huge green monster towering over him! They fire at the beast, but the phaser blasts bounce harmlessly off of it's hide. Spock orders the security guards to fire their weapons into the creature's mouth, which is not covered by scales. The attack is successful, and the dinosaur-like monster falls to the ground dead.
The Captain returns to the Enterprise, and is attended to by Dr. McCoy. Other than a gash on his head, and a slight concussion, he is fine. McCoy orders him to rest, but Kirk refuses and goes to the bridge in order to make contact with Starfleet Command. The Enterprise is ordered to escort an Omegan embassador home from Starbase 6. The mission is critical, since the Omegan alliance with the federation is shaky, and the slightest provocation could shift their loyalty to the Klingon Empire. Kirk is told to be extremely careful not to do anything that the ambassador could misinterpret as unfriendly.
The Enterprise reaches Starbase 6, and the ambassador (a tall bald man) is beamed aboard. He makes it known right away that he doesn't approve of the ship. Kirk and Spock make every attempt to be polite anyway, and the ship gets underway for Omega. At one point, Kirk asks Scotty what their current speed is. Scotty answers that the ship is doing warp 2. "Is that all?" says Kirk. "Increase to warp 4 immediately!". The engineer asks why, since the ship is making fine time. "I thought I gave you an order Mr. Scott!" Kirk replies, "And I'm not used to being disobeyed! Now you'll adjust our speed - or I'll know the reason why!".
Kirk gives the Omegan embassador a tour of the ship. A crewmember comes racing around a corner, late for duty, and knocks into the Omegan. He apologizes profusely, but Kirk orders him to the brig! Spock is nearby and watches the scene unfold. He suspects that something is wrong with the Captain and seeks Dr. McCoy's advice. McCoy agrees with Spock that the Captain has become short-tempered and domineering. The doctor theorizes that Kirk is suffering from after effects of the knock-out blow that he took on Beta II, but he believes that it is a temporary condition and should wear off soon. As McCoy and Spock are discussing the Captain's condition, he arrives in sick bay. Spock asks him if anything is wrong. "Well, let's just say that there are ways of dealing with those who plot against me!", Kirk says - and walks off. Spock expresses concern about what the Captain will do next.
Soon after, Kirk orders Mr. Sulu to change course "4.8 degrees". Sulu warns the Captain that the course change will send the ship through the center of the "8 Gamma Maelstrom - the nightmare pool of space", from which no ship has ever survived. "Then we'll be the first!" says Kirk. The ambassador arrives on the bridge just in time to watch as the ship plunges into the B-Gamma Maelstrom!
The opposing currents of the space whirlpool (illustrated as large green goblins grabbing the Enterprise hull!) threaten to tear the ship apart. Kirk orders full reverse until the ship is about to blow apart, and then changes thrust forward - pulling the Enterprise loose from the vortex. The Omegan embassador is less than impressed with Kirk's display. "The Klingons were right!" he says. "The Federation is composed of unreasoned, reckless fools!". He storms off the bridge.
Spock confronts the Captain about his behavior. Angered, Kirk orders the ship to go to full warp speed. Scotty protests this after the beating the ship has just taken from the whirlpool, and finally refuses the order - telling the captain that it would kill them all.
Kirk draws his phaser and shoots Scotty in the back. The stunned engineer is carried down to sick bay, and Spock, Sulu, and McCoy meet there to discuss the captain. Spock says that it is their duty to remove an "incompetent officer" from command, and orders a mutiny!
After spreading word of the plan, the three officers confront Kirk on the bridge and order him to remove himself from command. Kirk refuses and begins firing his phaser at the crewmembers, shouting "Rotten back-stabbers! You won't take me alive!". He runs through the ship to the shuttle bay, steals a shuttle craft, and escapes from the Enterprise into space. "Another example of Federation competency?" asks the ambassador, after Kirk's escape. Spock tells him that the man that just escaped from the ship was not James Kirk! He orders the ship back to Beta II.
Spock, the Ambassador, and several security guards beam down to the planet. They discover the stolen shuttlecraft abandoned on the surface. Using his tricorder, Spock leads the party to a cave entrance several feet away, and they enter. The Vulcan leads the landing party down a concealed stairway to a large cavern, where they discover TWO Kirks, along with a host of Klingons! The Enterprise crew quickly captures the Klingons. Spock explains that the Klingons had arranged the entire incident to discredit the Federation - thus insuring that Omega would side with them. They had faked the mineral deposits on the surface, and then arranged the "accident" so that they could replace the Captain with a duplicate of their own.
The duplicate Kirk makes a break for it. (The real) Kirk chases him, and they get in a fist-fight. When Spock arrives, he is not able to tell them apart until the fake Kirk asks Spock to kill (Something he says the real Kirk would never do). The Omegan embassador sees the treacherous ways of the Klingons, and vows to tighten his government's bonds with the Federation.