Ex Post Facto (Star Trek: Voyager)

"Ex Post Facto"
Star Trek: Voyager episode
The memory implanted into Paris
Episode no.	Season 1 Episode 8
Directed by	LeVar Burton
Teleplay by	Michael Piller Evan Carlos Somers
Story by	Evan Carlos Somers
Featured music	Dennis McCarthy
Production code	108
Original air date	February 27, 1995 (1995-02-27)
Guest stars
Henry Brown - Numiri Captain Francis Guinan - Minister Kray Aaron Lustig - Doctor Robin McKee - Lidell Ren Ray Reinhardt - Tolen Ren
Episode chronology
← Previous "Eye of the Needle" Next → "Emanations"
List of Star Trek: Voyager episodes

"Ex Post Facto" is the eighth episode of Star Trek: Voyager. The episode's title is Latin for "from a thing done afterward", and refers to the concept of retroactive law.

Plot

Ensign Kim returns to Voyager from a visit to a planet named Banea occupied by an avian people known as the Baneans 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 Baneans 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 memories depict Paris as being the same size as Ren's wife, when he is in fact taller than her, and knowing where the heart is located on a Banean, something he is not in fact aware of. 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 (who is the same size as Ren's wife) 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 Banea and continues its journey. In the mess hall, Paris thanks Tuvok, and tells him his actions have gained him a friend.

External links

• Ex Post Facto at the Internet Movie Database
• "Ex Post Facto" at TV.com
• Ex Post Facto at Memory Alpha (a Star Trek wiki)
• Ex Post Facto at StarTrek.com