During a tour of the dock and Marty, the DeLorean had a temporary glitch in the system navigation, and lifted in 2015 instead of year 2215. By that time, as a result of a few nuclear wars humanity has almost disappeared from the face of the Earth. The survivors have turned into vicious mutants. To save the life of doc and Marty turned his time machine by setting the power bumpers with studs, bars on the Windows, and air filter on the roof, in order to avoid contamination of radioactive dust.