Star Trek: Planet of the Titans

Star Trek: Planet of the Titans, also known as Star Trek: Planet of Titans, is an unproduced film based on Star Trek, which reached the script and design phases of pre-production. Following the success of Star Trek in broadcast syndication during the early 1970s and the popularity of the series at science-fiction conventions, Paramount Studios made several attempts to produce a feature film based upon the series. In 1975, Star Trek: The God Thing was proposed by franchise creator Gene Roddenberry but was not picked up by the studio.

The following year, pre-production began again on a film with a treatment and subsequent script called Planet of the Titans, produced by British writing team Chris Bryant and Allan Scott, with the intention of keeping costs down by filming in the United Kingdom. There were difficulties in ensuring that both William Shatner and Leonard Nimoy would sign to the film, as Shatner's deal with Paramount had expired, and Nimoy was concerned with unauthorized use of his image on merchandising. Philip Kaufman was signed to direct, after several other filmmakers were approached. The plot would have seen the crew investigating the homeworld of the mythical Titans. In escaping through a black hole, the crew is hurled into the prehistoric past where they teach early man how to make fire.

After their script was rejected, Bryant and Scott quit, and Kaufman created a new script treatment, but it too was rejected, and the project was killed on May 8, 1977, some two weeks before the release of Star Wars. Various reasons have been cited for the cancellation, including regime change at Paramount, and that executives thought they had missed their window due to Star Wars' imminent release, believing science fiction fans would not pay to see two such films. Paramount immediately changed course and launched a plan to take Star Trek back to television via a new network as Star Trek: Phase II.