SWAT指挥官瑞格（莱瑞克•本特 饰）突然被绑架，卷入了一场致命游戏，他必须在一个半小时之内过关斩将，躲过一个比一个恐怖的陷阱，才能保住性命。经验十足的FBI探员斯琼姆（斯科特•派特森 饰）来到被折磨得筋疲力尽的警察局，协助警探一起研究被竖锯玩死的受害者尸体，试图找出蛛丝马迹。随着调查的深入，竖锯变态的起因以及他邪恶的计划渐渐浮出水面……Jigsaw and his apprentice Amanda are dead. Now, upon the news of Detective Kerry's murder, two seasoned FBI profilers, Agent Strahm and Agent Perez, arrive in the terrified community to assist the veteran Detective Hoffman in sifting through Jigsaw's latest grisly remains and piecing together the puzzle. However, when SWAT Commander Rigg is abducted and thrust into a game, the last officer untouched by Jigsaw has but ninety minutes to overcome a series of demented traps and save an old friend or face the deadly consequences.