| Director | Michael Spierig, Peter Spierig |
|---|---|
| Genre | crime film, splatter film |
| Runtime | 92 min |
| Country | United States |
| Budget | $10 million |
| Box office | $104.2 million |
Detectives Brad Halloran and Keith Hunt pursue Edgar Munsen, who claims that he must start a "game" in exchange for his own survival. He activates a remote trigger, and is then shot and collapses.
Five people – Mitch, Anna, Ryan, Carly, and an unconscious man – awaken inside a barn with buckets on their heads and chains around their necks. A tape recording from John Kramer explains that they must each sacrifice blood to survive before the chains pull them towards a wall of buzzsaws. Most of the group escapes by cutting themselves, except for the unconscious man, who awakens too late. Their next test reveals that Carly, a purse snatcher, accidentally caused the death of an asthmatic woman. To save the others from being hanged, she must inject herself with one of three needles – one an antidote to a poison in her system, another being saline, and the last one acid. She refuses, so Ryan injects her with all three, killing her but saving the others. In their third test, Ryan attempts to escape the barn, but his leg falls through loose floorboards, and is ensnared by wires. Another tape recorder reveals that he will be punished for breaking the rules and must pull a lever to be "set free." Anna and Mitch become trapped inside a silo, forcing Ryan to pull the lever and sever his leg to rescue them.
Halloran and Hunt investigate the discovery of corpses that appear to be the unconscious man and Carly, whose deaths fit John's modus operandi. Halloran becomes suspicious of pathologists Logan Nelson and Eleanor Bonneville. Eleanor reveals to Logan that she is a Jigsaw fangirl, but now fears this might incriminate her. Hunt spies and informs Halloran. Later, Edgar is abducted from the hospital.
In the barn, Mitch is revealed to have sold a faulty motorcycle to John's nephew, causing his death, and is tested by being lowered into a funnel with a spiral-shaped blade powered by a motorcycle engine inside. He attempts to stop the blade, but is ultimately killed.
Edgar's corpse is found inside John's grave. Halloran finds a corpse appearing to be Mitch in Eleanor's studio and calls for her and Logan's arrest. Logan convinces Hunt to let them go after saying that the bullet which hit Edgar was fired by Halloran, whom he and Eleanor suspect to be the new Jigsaw Killer. Eleanor deduces the game's location and she and Logan depart for the barn, with Halloran in pursuit.
In the barn, Anna and Ryan are shackled to pipes at opposite ends of a room. John confronts them and reveals that Anna asphyxiated her baby and framed her husband, who later committed suicide, and Ryan's drunken tomfoolery caused his friends' death in a car accident. Meanwhile, Hunt finds jigsaw-shaped pieces of flesh in Halloran's freezer.
For their final test, John leaves the two a shotgun loaded with one shell, saying it is their key to freedom. Halloran ambushes Logan and Eleanor at the barn. Anna tries to shoot Ryan, but the gun backfires, killing her. Ryan finds the now-destroyed keys among the debris; they had been hidden inside the shell. Eleanor escapes Halloran, while an unseen assailant drugs him.
Logan and Halloran awaken in collars rigged with laser cutters and are told to confess their sins. Halloran forces Logan to go first; Logan confesses to mislabeling John's X-rays years earlier, causing his cancer to go undiagnosed. Despite confessing, Logan is apparently killed. Halloran then admits to allowing criminals to walk free for personal gain and his collar deactivates. Logan is revealed to still be alive, and also the unconscious man from the first barn game, which took place ten years earlier. Feeling that Logan should not die because of an honest mistake, John saved him and recruited him as his first apprentice. Logan reveals that he recreated the barn games, chose his victims from other criminals that Halloran let go, and framed Halloran as the new Jigsaw Killer as revenge for releasing Edgar, who killed Logan's wife. For breaking the rules by forcing Logan to go first, Halloran's collar is reactivated, slicing his head open. Logan says, "I speak for the dead," before shutting the door and leaving.