Kirk faces a court-martial over the apparent death of a crewman, until it emerges that the man faked his own death to frame him.
During an ion storm Kirk jettisons a pod with records officer Ben Finney inside, and the computer log seems to show he did so before going to red alert, which makes the loss look like negligence. At Starbase 11 Kirk is tried, prosecuted by his former girlfriend Areel Shaw and defended by the eccentric lawyer Samuel T. Cogley, who prefers books to computers. Finney's daughter Jamie blames Kirk.
Spock finds that the computer has been tampered with. With the crew sent off the ship, the sensors are set to pick up every heartbeat aboard, revealing that Finney is alive and hiding. Finney had altered the records to ruin Kirk, whom he resented, and Kirk confronts him in engineering.