Between the events of 'Saw' and 'Saw II', a sick and desperate John Kramer travels to Mexico for a risky and experimental medical procedure in hopes of a miracle cure for his cancer, only to discover the entire operation is a scam to defraud the most vulnerable. Armed with a newfound purpose, the infamous serial killer returns to his work, turning the tables on the con artists in his signature visceral way through devious, deranged, and ingenious traps.