The movie performed reasonably well at the box office. Having been made on a budget of $10,800,000, it went on to earn $56,000,000 at movie theaters in North America and a total of $114,000,000 worldwide.
Saw V contains scenes of torture and graphic bloody violence. There are instances of bad language and brief nudity in the film. The movie was originally rated NC-17 by the Motion Picture Association of America, the rating was later changed to R. An uncut and unrated version of Saw V has also been released in the United States and Germany. The film was banned in Malaysia.
Convicted murderer Seth Baxter awakens chained to a table beneath a pendulum blade. A videotape informs him that crushing his hands between the presses will release him.
The scene cuts to Agent Peter Strahm, who kills Jeff Denlon in self-defense and is sealed in the sickroom. He finds a hidden passage with a tape recorder that warns him to stay in the sickroom, but ignores it. He is attacked by a pig-masked figure in the passage and awakens with his head sealed in a box slowly filling with water, which he survives by performing a tracheotomy using a pen. Outside the plant, Detective Mark Hoffman delivers Corbett Denlon to the police and claims they are the only survivors, and is shocked when Strahm is brought out alive as well.
Jill Tuck is met by John Kramer's attorney, who is administering his will. She is left a box and a videotape, in which John stresses the importance of the box's contents. In a memorial service held for David Tapp, Steven Sing, Allison Kerry, Eric Matthews, and Daniel Rigg, the five officers killed in action, Hoffman is promoted to detective lieutenant. He is informed of the death of Agent Lindsey Perez while taking Strahm's phone and goes to the hospital to meet Strahm, who says that Hoffman's name was Perez's last words. Strahm is also met by his boss, Dan Erickson, who takes him off the case. Strahm then takes case files to research them on his own, determined to piece together Hoffman's involvement.
In an underground chamber, Ashley, Brit, Luba, Charles, and Mallick awaken with collars connected to mounted blades locked around their necks. The keys are in glass boxes across the room, though advancing will set off a one-minute timer. A videotape tells them to ignores their instincts during their tests. Mallick activates the timer, and everyone reaches their keys except Ashley, who is decapitated when the collars retract. In the next room, the four learn more about each other and Ashley, and learn by videotape that keys to the three shelters are in overhead jars. Brit, Luba and Mallick retrieve keys, but Charles attacks and takes it from Mallick, only to be struck by Luba and left to die in the explosion. Luba tries to use Mallick's body to close the circuits, but Brit kills her and they use her body instead. In the fourth room, they find a machine fitted with circular saws and a beaker that requires ten pints of blood to open the door. They notice five armholes and realize that every room was set up for the victims to work together to survive the game. They also realize that everyone was connected through a building fire that killed eight people. With no other options, they saw their arms to provide the ten pints of blood.
Meanwhile, Strahm travels to past game locations and learns through his research that Seth Baxter was convicted of murdering Hoffman's sister, but was released five years later on a technicality. He was later murdered by Hoffman, who used the pendulum blade to frame Jigsaw.
Strahm ultimately learns that everyone was meant to die in the plant except Corbett and Hoffman, who would give her to the police and be the hero who closed the case. Strahm soon draws Erickson's worry, which is fueled when Jill approaches him claiming that Strahm is stalking her. He is also called by Hoffman, who tells him of Strahm's belief in another accomplice.
Erickson puts a tracker on Strahm's phone and follows it to the current game's observation room, where Hoffman had planted it along with Erickson's file. He finds Brit, who crawled from the fourth room after Mallick passed out, and calls for medical assistance before placing an APB on Strahm, believing that he is the accomplice. Simultaneously, Strahm follows Hoffman to the renovated nerve gas house and finds an underground room containing a clear box filled with broken glass. Hoffman's tape urges Strahm to enter the box, but he stops it short and ambushes Hoffman, sealing him in the box after a brief struggle.