Does spontaneous human combustion exist? That is the question fire assistant investigator Roy Honda faces when the cremated body of Michael Fay is discovered in an undamaged bedroom. While his boss is sure the death is nothing more than a smoking mishap, Roy is unconvinced. Digging into the truth, he learns that spontaneous combustion of the human body is indeed real and that high concentrations of metabolic acetone are responsible. But when he discovers this rare and terrifying phenomenon can be triggered by artificial means-in the form of a poison pill-the truth could get him killed.