He salvaged the damaged DeLorean time machine and found a charged battery from the car, which he used to power one of the hoverwheels barely attached to the DeLorean. Separating the hoverwheel from the car, Marty attached the battery to it. The wheel's hubcap promptly began to glow and it quickly began to rise. Marty jumped on and used it to hover over the South Gate wall into Hill Valley. Once over the wall, he lost his balance and fell off. The wheel sailed into the sky, but the job was done: Marty was inside Hill Valley.