When oil is discovered in 1920s Oklahoma under Osage Nation land, the Osage people are murdered one by one—until the FBI steps in to unravel the mystery.

Inside a long-abandoned mine lurks a dark being which haunts the descendants of the miners who trapped it. When Luke's niece is suddenly struck with a strange form of schizophrenia, he re-opens the mine in hopes of raising the money to get her better treatment. But in order to truly save her, he must face the family curse.

Stranded in 1955, Marty McFly receives written word from his friend, Doctor Emmett Brown, as to where can be found the DeLorean time machine. However, an unfortunate discovery prompts Marty to go to his friend's aid. Using the time machine, Marty travels to the old west where his friend has run afoul of a gang of thugs and has fallen in love with a local schoolteacher. Using the technology from the time, Marty and Emmett devise one last chance to send the two of them back to the future.