Saw

Saw is a 2004 American psychological horror film directed by James Wan. It is the first installment of the seven-part Saw franchise with it's story revolving around two men who have been trapped in an abandoned industrial bathroom and they are given instructions via a microcassette recorder on how to escape by following the "rules" of their "game". Meanwhile, police detectives investigate and attempt to apprehend the criminal responsible.

Plot
Adam, a photographer, awakens in an abandoned industrial bathroom and finds himself chained at the ankle to a pipe. Lawrence Gordon, an oncologist, is summarily shackled across the room, and between them is a corpse holding a revolver and a microcassette recorder. Each man has a tape in their pocket and Adam is able to retrieve the recorder. Adam's tape urges him to escape the bathroom while Lawrence's tape tells him to kill Adam by 6:00 or his wife and daughter will be killed and he will be left to die. Adam eventually finds a bag containing two hacksaws inside a toilet tank; they attempt to cut through the chains, but Adam's saw breaks and he angrily throws it at the mirror in frustration. Lawrence realizes that the hacksaws are mean't for their feet and identifies their captor as the Jigsaw Killer, whom Lawrence knows about because he was a suspect five months before.

Flashbacks show that while Lawrence was discussing the terminal brain cancer of a patient, identified as John by an orderly named Zep Hindle, with his medical students, he was approached by Detectives David Tapp and Steven Sing, who found his penlight at the scene of a Jigsaw "game", of which at least three have been investigated. Lawrence's alibi clears him but he reluctantly agrees to view the testimony of the only known survivor, a heroin addict named Amanda Young, who believes Jigsaw has helped her from a "reverse bear trap".

Meanwhile, Alison and Diana Gordon are being held captive in their home by Zep, who is watching Adam and Lawrence through a camera behind a two-way mirror in the bathroom. The house is simultaneously being watched by Tapp, who has since been discharged from the force. Flashbacks show that Tapp became obsessed with the Jigsaw case after hearing Amanda's testimony, and eventually discovered Jigsaw's warehouse using the videotape from her game. He and Sing entered the warehouse, where they apprehended Jigsaw and saved a man from a drill trap, but Jigsaw escaped after slashing Tapp's throat and Sing was killed by a shotgun trap while pursuing him. Convinced that Lawrence was Jigsaw, Tapp began stalking him after his discharge.

In the bathroom, Lawrence finds a box containing a lighter, two cigarettes and a one-way cellphone. He then recalls his abduction: he was trying to use his phone after being trapped in a parking garage, and was suddenly attacked by a pig-masked figure. They try using a cigeratte dipped in the corpse's "poisoned" blood to stage Adam's death, but the plan fails when Adam was zapped through the ankle chain. At gunpoint, Alison calls Lawrence and tells him not to trust Adam, who admits that he was being paid to take photos of Lawrence, many of which were in the hacksaw bag. Adam also reveals his knowledge of Lawrence's affair with one of his medical students; Lawrence had been with her before he was abducted. Lawrence realizes from Adam's description that Tapp was paying him. Adam finds a photo that he didn't take, of a man staring out a window of Lawrence's house, whom Lawrence identifies as Zep. Unfortunately, the clock then strikes six as he realizes this.

As Alison, who manages to free herself, calls Lawrence at gunpoint again, she fights Zep for the gun. The struggle gets Tapp's attention, and he saves Alison and Diana and pursues Zep to the sewers, where he is eventually shot during the struggle. Lawrence, aware only of gunshots and screaming, is zapped as well and losing reach of the phone; in desperation, he saws off his foot and shoots Adam with the corpse's revolver. Zep enters the bathroom to kill Lawrence but is knocked down and beaten to death with a toilet tank cover by Adam, who only suffered a flesh wound. As Lawrence crawls out of the room to find help, Adam searches Zep's body for a key and finds another microcassette recorder, which reveals that Zep was another victim, following the rules of his own game to obtain an antidote for a slow-acting poison in his body. As the tape ends, the "corpse" rises and is revealed to be Lawrence's patient, John, the real Jigsaw Killer. He says the key to the chain is in the bathtub, which was drained when Adam awoke. He zaps Adam when he tries to shoot John and loses reach of Zep's pistol, and then John turns off the lights and seals the door, leaving Adam to die, telling him "game over".