Arson Inspector Morgan Conrad has come to the police for help. A building burned down under what she believes is suspicious circumstances but, since the fire superficially appears to be accidental, she is getting no support from her department. Shawn and Gus, who used to want to be firemen when they grew up, volunteer their assistance. Shawn, Gus, Lassiter and Juliet go with Morgan to the scene where they run into her boss, Army Johnson, who tells them that the building had no fire insurance, so there is no motive for arson. Plus, arson is so rare, he hasn't seen a case since way back to his firefighting days. But Morgan counters that one of the fireman on the scene reported smelling something sweet, a sign of an accelerant. As Shawn looks around the scene, he notices that one of the walls lacks insulation. He grabs a pipe and smashes it into the wall, revealing a blackened skeleton hidden inside. Now it's not just arson, it's murder.