Spock steals the Enterprise to deliver the crippled Captain Pike to a forbidden world, and a court-martial reveals why.
The Enterprise is called to Starbase 11 by a message said to come from Captain Christopher Pike, Spock's former commander, though Pike, now paralysed and unable to speak after a radiation accident, could not have sent it. Spock then uses forged orders to take the ship, with Pike aboard, toward Talos IV, a world Starfleet forbids anyone to visit on pain of death.
Kirk and Commodore Mendez catch up, and Spock asks for a court-martial, which is held aboard the ship as it travels. As evidence, Spock shows images of Pike's earlier visit to Talos IV, using footage from the unaired pilot The Cage. This is the first half of the original series' only two-part story, which won a Hugo Award.