The game's plot revolves around David Tapp's son, Michael Tapp, searching for the truth behind his father's suicide after the events of the first game. He starts to get into deep secrets and is captured by the Jigsaw Killer before learning everything. Now in order to escape and get revenge, Michael must go through trials and traps to survive. Trapped with him is a group of corrupt individuals including dirty cops, drug addicts, murderers, a nurse, and a money laundering accountant.
Campbell Iman - The first playable character in SAW II. His actions play a part in which ending the player gets. After playing through his prologue, focus switches to...
Michael Tapp - The son of David Tapp, the protagonist from the first game. Michael is an investigative reporter who reported on the Jigsaw killer and his father's investigations. His actions ultimately result in his father's losing his job as a police detective. Michael also seems to have other corrupt ties with other individuals in the police department.
Chief Henry Jacobs - The chief of police. He is somehow involved in corruption and the death of David Tapp. It is implied that Michael has helped him and others cover up certain illegal activities in the past.
Sarah Blalock - An informant for David Tapp back in his detective days. It's implied they had some sort of romantic relationship.
Joseph Poltzer - The head vice detective, Joseph is neck-deep in the corruption of the police department. He appears to have some hand in setting David Tapp up to take a fall with Michael Tapp's help.
Carla Song - A corrupt nurse that supplies drugs to a drug ring run by dirty cops.
Solomon Bates - The money man, involved in covering up the bookkeeping elements involved in the police department's corruption.
Jigsaw - The big bad himself.