o avoid a confrontation with Romulans, Kirk orders the ship through a unknown energy field. They escape the Romulans, but the energy field has changed the ship's computer into a prankster. It begins pulling more and more complicated practical jokes on the crew, finally to the point of endangering McCoy, Uhura, and Sulu on the Recreation Deck. Besides those three's lives, the Romulans re-appear and threaten the ship. The practical-joking computer actually helps distract the Romulans for a short while, but then the ship is once again set upon. Kirk tricks the computer (using reverse logic) into re-entering the energy field, which restores the computer to normal, but makes the Romulans' computers into pranksters instead.

Résumé de IMDb.com