A killer named Edgar Munsen is being followed by the police on a roof where a mechanism works. He is severely shot and hurt by police officer Halloran and other colleagues of his own. Elsewhere, five people are held captive in a barn, each of them having a metal rod around his neck that leads them to a puzzle wall. A record by John Kramer explains that they must shed their own blood and, ultimately, confess their sins committed.The gun starts to pull them to some saw blades. Four of them manage to survive by cutting and offering blood, while the third, who was unconscious in most of the time, dies. The next test reveals that one of the members, Carly, accidentally caused the death of a woman suffering from asthma and stole her purse in which her inhaler was. Three syringes are then revealed.One of them contains the antidote for the poison in its system, another saline solution, and the third one an acid. She has to choose one of the syringes to inject to save the others from death by hanging. During the games, Halloran and his partner, Detective Hunt, begin to investigate the matter after discovering the bodies of an unknown person and Carly, both of whom were killed in the barn. In another room, Ryan tries to trick and escape a door marked “No Exit,” but his foot is trapped in a trap that blocks him.