A young man named Adam wakes to find himself chained to a rusty pipe inside a decrepit subterranean chamber. Chained to the opposite side of the room is another bewildered captive, Dr. Lawrence Gordon. Between them is a dead man lying in a pool of blood, holding a .38 in his hand. Neither man knows why he has been abducted; but instructions left on a microcassette, order Dr. Gordon to kill Adam within eight hours. If he fails to do so, then both men will die, and Dr. Gordon's wife, Alison, and his daughter will be killed. Recalling a recent murder investigation by a police detective named Tapp, Dr. Gordon realizes he and Adam are the next victims of a psychopathic genius known only as "Jigsaw." With only a few hours left to spare, they must unravel the elaborate puzzle of their fate in the midst of mounting terror. The killer has provided them with only a few clues and two handsaws – too weak to break their steel shackles, but strong enough to cut through flesh and bone.