Episode Information
About this episode
The Alternative Factor is season 1, episode 20 of Star Trek: The Original Series, first aired on 30 March 1967.
In series order, the previous episode is S01E19 — Arena and the next is S01E21 — Tomorrow is Yesterday. By original air date, the previous episode is S01E27 — Errand of Mercy and the next is S01E28 — The City on the Edge of Forever.
Browse every episode in Season 1.
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