Stardate: 5943.7
Original airdate: 3/14/1969
Writer: Jean Lisette Aroeste
Director: Marvin Chomsky

Guest Stars:

Mariette Hartley        Zarabeth, human woman condemned to a frozen wasteland by ZorKhan
Ian Wolfe               Atoz, the librarian on Sarpeidon
Kermit Murdock          Prosecutor
Johnny Haymer           Constable
Stan Barrett            Jailer
Ed Bakey                Fop
Al Cavens               Fop
Anna Karen              Woman

Story:
Kirk, Spock and McCoy beam down to Sarpeidon to rescue inhabitants before its sun explodes. But they arrive to find only the planet's librarian, who has helped all the others to safety via a time machine. When Kirk accidentally enters the past, Spock and McCoy attempt a rescue, emerging in the Sarpeidon ice age. Spock, now a throwback to earlier Vulcan times, falls in love with a beautiful woman and has no intention of returning to Kirk or the Enterprise.

Beta Niobi: The sun going 'Nova' in 4 hours, threatening the world, Sarpeidon.

Sarpeidon: Class M planet with civilized and advanced humans but no one is there.

Atavachron: machine linked to the library that prepares persons to live in a historical period on Sarpeidon. The machine changes the persons cell structure or the person will die within a few hours in the past.

Quotes:
"You're very late. Where have you been?" Mr. Atoz.
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