One of the biggest landmark television series in science fiction history, the original “Star Trek” used high-quality model work and the most cutting-edge visual effects of its day to achieve a believable 23rd-century setting. Even Gene Roddenberry was not immune to budget constraints, and in the middle of the show’s groundbreaking first season, producers found themselves running out of time and money (via StarTrek.com). Unable to continue meeting the network’s tight deadlines to deliver the episodes, Roddenberry and his crew had the clever idea to recycle an entire episode to become a two-part story that would help solve both problems.

This would be no clip show, but a new story built around the original unaired pilot that the studio had famously rejected the year before titled “The Cage.” In the new episode, “The Menagerie,” Mr. Spock steals the Enterprise to help his former captain, Christopher Pike, but is caught and put on trial. More than half of the episode’s runtime is a flashback, with Spock relating a previous mission he’d been on with Pike, all recycled from the original pilot episode. Because “The Cage” had never aired, viewers were none the wiser. More than a decade passed before fans realized there was an entire unseen episode out there somewhere.

“The Cage” aired for the first time in 1988, and is now included on DVD box sets and Paramount+, the studio’s streaming service, for anyone to watch.