Predatory lenders Simone and Eddie awaken on either side of a room split by a cage containing a scale, wearing head harnesses with screws poised to pierce their temples. They learn via videotape that the one who sets more flesh weight on their tray will survive. Eddie cuts fat from his torso, but Simone chops off her arm, which tilts the scale in her favor; the timer expires, and Eddie is killed by the screws. While he reviews the game’s footage, Detective Lt. Mark Hoffman is called to the scene by FBI Agent Dan Erickson, who found Agent Peter Strahm’s fingerprints around the room. Also present is Agent Lindsey Perez, whose survival was covered up by Erickson for her protection. They learn from Dr. Adam Heffner, who performed all of the autopsies for the Jigsaw case, that the knife used to cut the jigsaw piece from Eddie’s flesh was only used on Seth Baxter before then. The agents intend to find the Baxter videotape to prove Strahm’s involvement. At Umbrella Health, insurance executive William Easton meets with Debbie, the company’s attorney, about Harold Abbott, who succumbed to heart disease after his request for coverage was denied due to an application discrepancy. While at the hospital to meet with an embittered Simone, Hoffman is met by reporter Pamela Jenkins, who claims she found something at the meatpacking plant. He also meets with Jill Tuck at her clinic and is given six envelopes containing photos of people to be tested, including William, from the box left to her in John Kramer’s will. A flashback reveals that Kramer brought Amanda Young to Jill, who had deemed Amanda a lost cause, as proof of his methods. While at the hospital later to deliver a package from the box, another flashback shows that Jill met with Kramer at the plant hours before his death, where he gave her the box’s key and his promise that she would be protected when the games ended. The same flashback reveals the antagonistic partnership between Hoffman and Amanda. That night, Hoffman abducts William from his office and brings him to an abandoned zoo. William awakens in a vise designed to tighten around his torso each time he breathes into the oxygen mask strapped to his face. His janitor, Hank, is in the same trap across from him. He learns from a videotape of Kramer himself that he must undergo four tests to remove the bombs locked to his limbs, and he will lose his family if the tests are not finished within one hour. Hank, who is a heavy smoker, is unable to hold his breath for long and is killed by the vise. The other tests force William to save his staff and associates from their own traps, usually by choosing between them, as a means of confronting his own probability formula, which favors the healthy over the ill. Flashbacks throughout the tests show that Kramer met William at the opening of Jill’s clinic and took issue with his formula. After his cancer was diagnosed, Kramer’s applications for coverage for an experimental Norwegian treatment were rejected by William. The game is viewed by a woman named Tara and her son Brent, who awaken below the observation room in a cage, which contains a tank of hydrofluoric acid and a switch marked “Live” and “Die”. Pamela awakens in another cage on the other side of the room. During the game, Hoffman is called away by Erickson and Perez, who were informed of abnormalities found in Strahm’s fingerprints. They also found the Baxter videotape, though the voice did not match Jigsaw’s; a technician is currently unscrambling the voice at an off-site lab. At the lab, Erickson reveals their knowledge of Strahm’s death to Hoffman, who kills everyone in the room the moment his voice is unscrambled. He plants fingerprints using Strahm’s severed hand and sets the room on fire to destroy the evidence. Hoffman returns to the observation room and finds the letter he’d written to Amanda, in which he used his knowledge of her role in Jill’s miscarriage to blackmail her into killing Lynn Denlon. Pamela found the letter at the plant and gave it to Jill, who uses it to ambush Hoffman as William reaches the end of his path with one second left. He finds himself between the cages and immediately rushes to Pamela, his sister. Tara, Harold’s wife, is informed by a videotape of Kramer that she can kill William or free him using the switch. When she is ultimately unable to kill him, Brent angrily shifts the switch and a platform of needles swings down and injects William’s body with the acid, killing him. Jill restrains Hoffman and locks a new reverse bear trap to his head. She shows him the sixth envelope, which contains his photo, and leaves him with 45 seconds but no key. He escapes by breaking his hand and jamming the trap as it activates, though his cheek is ripped open as he removes it. The film cuts to black as he screams.