Captain Chandra
Reginald Lalsingh

Commodore Stone
Percy Rodriquez

Samuel T. Cogley
Elisha Cook Jr.

Jamie Finney
Alice Rawlings

Timothy
Winston DeLugo

Lt. Areel Shaw
Joan Marshall

Lt. Commander
Benjamin Finney
Richard Webb

Lt. Hansen
Hagan Beggs

Captain Krasnowsky
Bart Conrad

Space Command
Representative Lindstrom
William Meader

During an ion storm a crewman, Records Officer Ben Finney, is killed when Kirk is forced to eject the sensor pod in which he is stationed. Returning to Starbase 11 for repairs, Kirk sends a full report to the Port Master, Senior Captain Stone. A discrepancy is found between the Captain's log and the ship's computer records which leads to James T. Kirk becoming the first Starfleet Captain to face court martial.

The prosecuting attorney assigned to the case is Areel Shaw, one of Kirk's old flames. His own lawyer is an old-fashioned eccentric called Samuel T. Cogley. During the trial Kirk relates how he and Finney served together on U.S.S. Republic NCC 1371 where he had been forced to report Finney for negligence, an act which had severely damaged Finney's promotion prospects. Despite this, Finney had apparently forgiven him and had agreed to serve with him aboard the Enterprise.

They had, at one time, been such good friends that Finney's daughter, Jamie, had been named after him. Of the incident, Kirk testifies that he had put the Enterprise on red alert and had given Finney a chance to leave the pod before jettisoning it but the computer records show that it was apparently ejected while the ship was only in a state of yellow alert.

In the meantime Spock has been carrying out his own tests on the ship's computer and comes to the conclusion that, somehow, the computer records have been altered. Finney was one of only three people aboard the Enterprise with the ability to do this, the other two being Spock and Kirk himself, and that his captain is the victim of a sophisticated frame-up. Cogley brings up an old law that allows the accused to face his accuser, in this case the ship's computer, and the scene of the trial is moved aboard the Enterprise.

All non-essential crew are beamed off ship and, one by one, the remaining personnel have their heartbeats masked from the ship's auditory sensors. When all have been done, one heartbeat remains - that of Ben Finney. They track him down to main engineering, where Kirk confronts him and demands an explanation for his actions. Driven mad by jealousy and a desire for revenge over the years, he attacks Kirk but, on hearing that his daughter Jamie is on board, relents and confesses to his actions after which he is taken into Starfleet custody to face charges.