Star Trek: Season 3, Episode 20

3 - 20: The Way to Eden

The Enterprise intercepts a stolen space yacht, whose thieves destroy it rather than face capture. But they are captured, and revealed as "counterculture" individuals looking for a mysterious planet they call Eden. Led by an insane genius, they manage to capture the Enterprise long enough to direct it to Eden, which is located in the Romulan Neutral Zone! And to make their escape, they create a lethal trap for the crew.