Photographer Adam Stanheight awakens in a dilapidated bathtub, with his ankle chained to a pipe. Across the room is oncologist Lawrence Gordon with a corpse between them holding a revolver and a microcassette recorder. Both men find a tape in their pockets, and Adam retrieves the recorder. Adam's tape urges him to escape, while Lawrence's tape tells him to kill Adam by six o'clock or his wife Alison and daughter Diana will be killed and he will be left to die. Adam finds a bag containing two hacksaws inside the toilet, which they try to use to cut through their chains, but Adam's saw breaks. Lawrence realizes the saws are meant to be used on their feet, and identifies their captor as the Jigsaw Killer, whom Lawrence knows of because he was once a suspect.
