The USS Enterprise orbits the planet Psi 2000, a world that was much like Earth in its distant past, tasked to observe the planet’s impending disintegration. Lieutenant Commander Spock and Lieutenant Junior Grade Joe Tormolen beam down in environmental suits to a frozen surface laboratory and investigate the horrific deaths of the lab’s scientists. Carelessly, Tormolen removes a glove of his suit to better scratch his nose, unknowingly exposing himself to a red, blood-like liquid substance leaping to his exposed hand from a frozen wall. Spock contacts the Enterprise and informs Captain Kirk that all of the station’s personnel are dead. Kirk asks what caused it and Spock replies, “Unknown, captain. It’s like nothing we’ve dealt with before.”
The Enterprise crew is intoxicated by an inhibition-stripping contagion that causes mayhem throughout the ship.
The episode’s writer, John D.F. Black, came up with Sulu’s “berserk” scenes without specifying the weapon to be used. Unable to decide between a samurai sword or a fencing foil, he left the choice to George Takei, who picked the latter with the thought that by the 23rd century Humanity would have developed to a point where, in terms of culture, people have moved beyond simply adhering to ways of their ethnic background.
This episode is considered a bottle show, as it contains no villain and only regular characters, and takes place almost entirely aboard the Enterprise. According to Black, at the time both Riley and Tormolen were under consideration to become regulars.
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Watch the trailer on the TrekCore YouTube Channel.