James Wan's mould-breaking psycho thriller opens in a derelict public toilet. Two men, Adam (Leigh Whannell) and Dr Lawrence Gordon (Cary Elwes) are chained to the walls by leg irons. Between them are a corpse, a gun, a tape recorder and a saw. They are the latest victims of the Jigsaw Killer, a serial killer with a penchant for setting up bizarre scenarios for his victims. Only one of the men will walk (or rather, hobble) to freedom. On the killer's trail are cops David Tapp (Danny Glover) and Steven Sing (Ken Leung). Can they find his latest victims before time runs out?
Wan, who wrote the original story, co-scripted with the film's star Whannel. They take elements of The Silence of the Lambs and Se7en but offer their own original take on innocents (or supposed innocents, as the plot development shows) in mortal peril.
To some extent, the Jigsaw Killer is their plot device to get Adam and Gordon into their predicament, setting them against each other, but in the parallel story of the two detectives tracking him down, his previous escapades give substance to his development as a malevolent killer whose identity and motives, when revealed, wrap up the preceding horrors.