Marty and Doc are at it again as the time-traveling duo head to 2015 to nip some McFly family woes in the bud. But things go awry thanks to bully Biff Tannen and a pesky sports almanac. In a last-ditch attempt to set things straight, Marty finds himself bound for 1955 and face to face with his teenage parents -- again.

A police chief in the war-torn streets of Los Angeles discovers that an extraterrestrial creature is hunting down residents - and that he is the next target.

A renegade Vulcan with a startling secret hijacks the U.S.S. Enterprise in order to find a mythical planet.

After years of war, the Federation and the Klingon empire find themselves on the brink of a peace summit when a Klingon ship is nearly destroyed by an apparent attack from the Enterprise. Both worlds brace for what may be their deadliest encounter.

The final installment finds Marty digging the trusty DeLorean out of a mineshaft and looking for Doc in the Wild West of 1885. But when their time machine breaks down, the travelers are stranded in a land of spurs. More problems arise when Doc falls for pretty schoolteacher Clara Clayton, and Marty tangles with Buford Tannen.