Eighties teenager Marty McFly is accidentally sent back in time to 1955, inadvertently disrupting his parents’ first meeting and attracting his mother’s romantic interest. Marty must repair the damage to history by rekindling his parents’ romance and – with the help of his eccentric inventor friend Doc Brown – return to 1985.
The world of Eternia in the aftermath of Skeletor’s war on Castle Grayskull, which he has won after seizing Grayskull and the surrounding city using a cosmic key developed by the locksmith Gwildor. The Sorceress is now Skeletor’s prisoner and he begins to drain her life-force as he waits for the moon of Eternia to align with the Great Eye of the Universe that will bestow god-like power upon him.
During a shootout in a saloon, Sheriff Hunt injures a suspicious stranger. One of the villagers takes care of him in prison. One day they both disappear – only the spear of a cannibal tribe is found. Hunt and a few of his men go in search of the prisoner and his nurse.
Marty and Doc are at it again in this wacky sequel to the 1985 blockbuster 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.