Following Jigsaw's grisly demise, Mark Hoffman becomes the final apprentice to the serial killer and is deigned a hero. Meanwhile, Agent Strahm is tested and puts the pieces together. While Strahm realizes that Hoffman is helping Jigsaw, five seemingly unconnected people are kidnapped and forced to complete a series of tasks in order to survive. Strahm follows all the leads that Hoffman gives him, including information on the death of his sister and why he joined Jigsaw. Hoffman and Strahm circle each other until it boils down to a gruesome and bone-crushing finale.