Star Trek: Season 1, Episode 24

1 - 24: This Side of Paradise

The Federation established a colony on Omicron Ceti III before it knew that the system's star emitted Berthold Rays, which degrade animal tissue. Tolerable for short periods with precautions, these rays spelled doom for the colony. So how are they still alive, and in better health than when they left Federation space? And perhaps more importantly, why have they accomplished... nothing? The answer threatens the Enterprise...