On the evening of their engagement party, Maine Game Warden Investigator Mike Bowditch and Stacey Stevens witness what seems to be a hit-and-run speedboat crash on a darkened lake. When they arrive at the scene, their spotlight reveals a gruesome sight: a severed arm floating just beneath the surface. As day breaks, the warden dive team recovers not one but two naked corpses: a dismembered man and the married woman with whom he was having an affair. Mike begins to suspect the swimmers' deaths were not a senseless accident but a coldly calculated murder.