• Production Code: 75
• Stardate: 5832.3
• Original Air Date: Feb 21, 1969
• Writer: Arthur Heinemann
• Director: David Alexander
• Guest Stars:
  • Skip Homeier (Sevrin)
  • Charles Napier (Adam)
  • Mary-Linda Rapelye (Irina)
  • Majel Barrett (Nurse Chapel)
  • Victor Brandt (Tongo Rad)
  • Elizabeth Rogers (Lt. Palmer)
  • Deborah Downey (Girl #1)
  • Phyllis Douglas (Girl #2)

Pursuing the USS Aurora, which has been stolen, Kirk beams the Aurora's crew aboard the Enterprise when the sustained high-speed pursuit overloads the stolen vessel's engines, destroying the ship. The thieves turn out to be a motley assortment of "hippies," including noted scientist Dr. Sevrin. Another of the throwbacks is the son of a Federation ambassador, leading Starfleet Command to order Kirk to allow his new passengers to roam the Enterprise freely. Sevrin and his friends take advantage of their newfound freedom and decide to hijack the Enterprise so they may resume the interrupted mission for which they stole the Aurora - to find the mythical planet Eden, a gardenlike world on which they hope to find health, purity and happiness.

Note: The planet Eden is also mentioned in "Star Trek V: The Final Frontier," and although Sybok was obviously thinking about a different Eden when he and his followers took over the Enterprise for much the same purpose as Dr. Sevrin and company, Kirk, perhaps remembering this adventure, stated many times in "The Final Frontier" that Eden, as a planet, is a myth.