While investigating the bloody aftermath of a grizzly murder, Detective Eric Mason (Donnie Wahlberg) has the feeling that it is the work of Jigsaw, the notorious killer who disappeared leaving a trail of bodies -- and parts -- behind. And Mason is right. Jigsaw is at work again. But instead of two people locked in a room with only one unthinkable way out, there are eight. Eight strangers -- unaware of their connection to each other -- forced to play out a game that challenges their wits and puts their lives in jeopardy.