Ensign Kim returns to Voyager from a visit to a planet occupied by a people known as the Banea with news that Lieutenant Paris, who was also on the trip, has been accused and convicted of the murder of the scientist, Tolen Ren, with whom they were working.
Voyager is flown in to investigate this conviction, and encounters a patrol ship governed by the Numiri, a race with which the Banea are at war. The patrol allows Voyager to enter the warzone with no resistance.
Paris denies the accusation of murder but the evidence, being the very last memories of Ren's life extracted from his mind, show otherwise. These memories have been implanted by a Banean doctor into Paris' mind, so that he regularly relives the murder through the eyes of his victim, as required by the Banean justice system. However, Paris becomes ill as a result and the Banean doctor permits Captain Janeway to take him to Voyager for evaluation, while Chief of Security Tuvok visits the planet to investigate for himself.
At this point, the Numiri launch an attack on Voyager, but fail.
Tuvok decides that he must see the memories for himself and performs a mind meld with Paris, during which he sees unusual script superimposed on the visions. When the mind meld is complete, Tuvok believes he has enough evidence to secure Paris' innocence, and can explain the Numiri attack.
It transpires that the Banean doctor is a spy for the Numiri, and altered the memories as they were extracted from Ren's mind, so that it appeared that Paris was the murderer. The final key to Tuvok's successful examination is the fact that the dog does not bark at the doctor, but instead is very familiar with him. (This device was first seen in Sir Arthur Conan Doyle's "Silver Blaze"). Then, when the memories were implanted into Paris, they were altered by the doctor further to incorporate sensitive technology information. By permitting Paris to leave the planet and return to Voyager, the doctor was providing the perfect opportunity for the Numiri to acquire Paris and with him the stolen information.
Paris is released, and the doctor arrested along with Ren's wife who was complicit in the murder of her husband. Voyager leaves the Banean homeworld and continues its journey.