Long before J.J. Abrams rebooted the franchise with Chris Pine and Zachary Quinto as Kirk and Spock, the original Star Trek series spawned an entire series of movies as well. In the first Trek movie, the crew of the USS Enterprise faces off against a mysterious alien entity that's destroying everything in its path en route to its ultimate destination: Earth. There are a total of six movies in the film series based on the original series, and, technically, the original continuity does link up with the Abrams reboot as well.
Watch Star Trek on Netflix or watch Star Trek: The Motion Picture on Hulu.