The Return of the Archons

"The Return of the Archons" is the twenty-first episode of the first season of the American science fiction television series Star Trek. Written by Boris Sobelman (based on a story by Gene Roddenberry), and directed by Joseph Pevney, it first aired on NBC on February 9, 1967.

In the episode, the crew of the Enterprise visit a seemingly peaceful planet whose inhabitants are "of the Body", controlled by an unseen ruler, and enjoy a night of violence during "Festival".

The episode contains Star Trek's first reference to the Prime Directive.