Sam has a miserable life. His wife cheats on him, people make fun of him for his weight, and he hates his bus driver job. When Satan appears to him and pushes Sam to kill his wife, Sam thinks he can do so until he actually tries. After backing out, he sinks further into depression and does something unthinkable – crashes his bus full of passengers, killing everyone on board.

The bus appears randomly on its normal route and picks up a stray passenger who is never seen alive again. When a detective's kids are next on its stop, he must race against the clock in order to rescue them from the phantom bus before they become its next victims.