Milwaukee homicide detective Ellie MacIntosh is called to an arson scene. She finds bewildered home owners, an unidentified corpse, and cryptic clues that lead nowhere. Is it a random killing? The ritualistic nature of the crime points to no, and Ellie fears that the already-oppressive summer is just starting to heat up. Ellie doesn't like her obnoxious new partner, Jason Santiago. That's fine with Jason--he doesn't like her either. When Ellie becomes convinced that their investigation is tied to a cold case, Jason finds himself grudgingly starting to agree. It might be hot as hell outside, but the details of the brutal homicide chill him to the bone... As fires rage and the body count rises, Ellie and Jason must put their personal disagreements aside to catch a ruthless killer. The heat is on.