Doctor Who: Full Circle, Episode 3 (1980)

Synopsis
In the third episode of the four-part story "Full Circle," the Doctor (Tom Baker) realizes that he and Romana (Lalla Ward) have been marooned in E-space on the planet Alzarius, where the full evolutionary cycle repeats itself every 50 years. He also makes a startling discovery about the "disabled" starliner where he and several other space castaways have been confined. Written by Andrew Smith, "Full Circle, Episode 3" was originally telecast on November 8, 1980. ~ Hal Erickson, All Movie Guide