Barnaby grudgingly begins to suspect that an arson investigator that he has trusted for years is involved in setting fires and then ruling them as accidental in order to get a cut of the insurance money.

An ex-cop and friend of Barnaby looks to even the score when his son is killed by a gang leader. Barnaby gets involved and learns that the gang is actually being used as muscle by a crooked businessman who wants the ex-cop out of the way.