As the Jupiter 2 is travelling along in space, it becomes necessary for Professor Robinson and Major West to clean impurities out of the reserve fuel cells by running the engines at full power. This results in an accident, propelling the Jupiter 2 past the speed of light, and into a time warp. When the Robinson party recovers from the accident, they discover that they are approaching the planet Earth. Upon landing, they discover that they have indeed travelled back in time. It is October, 1947. They have landed in a lumber mill parking lot in the rural town of Manitou Junction, Michigan.