The man who has devised some of the most devious crimes in recent memory, John Kramer aka Jigsaw (Tobin Bell), is finally dead and lies on the autopsy table where he is dissected. First his brain is removed, as the pathologist notes that there has been some recent surgery performed on it, and then the body is opened up. In the stomach is discovered a small plastic box, something the killer has swallowed before he died, and Detective Hoffman (Costas Mandylor), the man in charge of the investigation, is immediately called for inside the box is a mini cassette tape with a message on it: Jigsaw is by no means finished...
Whether that fills you with excitement or despair is very much dependent on your opinion of the Saw series, the most successful horror series of the early 2000s. Although the first film had some degree of quality in its twists, by the time we reached the third sequel it was all getting very samey, including bringing the director of the previous two back, Darren Lynn Bousman, and the inspiration was running out of steam, something which had been occurring since the second instalment. Nevertheless, someone must have been impressed because after this was a hit, Saw V was announced.
At least there was the gimmick of having the chief villain dead before the story began, but Bell returns through the magic of flashbacks in what amounts to an origin tale as we discover what made him the most sanctimonious bad guy of all time. Nobody could live up to the standards set by Jigsaw, and for some that's what makes him so powerful, that he takes such a high moral ground that his victims, most of whom had no idea beforehand that they were being set up by him and his minions, have little hope of solving his traps and proving themselves worthy.
As well as all that original business, there's a mystery too because we have to wonder who the final Jigsaw accomplice could possibly be. To bolster that plotline we see how someone could be transformed into one of the Machiavellian manipulator's followers in the form of series regular Rigg (Lyriq Bent) and the trials he is put through. After being persuaded to take a break from the case, he is alone in his apartment, his wife having left for a few days, when he is awoken by a strange sound. Next thing he knows he's in the bathtub and someone has set up a series of clues and more in his home, including a victim about to be killed if he does not intervene.
The point to this being, if Rigg didn't have such a drive to save people and allowed Jigsaw to play out his power trips, then he might actually be doing good. Believe that if you like, but there's more in that Rigg has to track down two police detectives captured by Jigsaw's unknown assistant and placed in mortal danger, one in danger of hanging if the block of ice he stands on melts, the other in peril of electrocution if the hanging is carried out. As always with the Saw sequels, they take a dim view of human nature in their "no one is entirely innocent" posturing, and equally predictable is the dim view of lighting, making this one of the dingiest-looking films since... well, since the last Saw film. Unless you buy into this cynical world, there's precious little to engage. Music by Charlie Clouser.