When temperatures drop in Loon Lake, Wisconsin, the lakes freeze over, tourists pack their bags and head home, and retired dentist Doc Osborne prepares for a much-needed respite. But this season, just as the weather gets colder, things heat up, as Police Chief Lew Ferris discovers a mystery buried under the icy waters...

It's ice-fishing season in Loon Lake and Doc Osborne is trying to convince Police Chief and fishing pal Lew Ferris to give it a chance. But fish aren't the only thing lurking below the surface. The bodies of two snowmobilers have just been pulled out of nearby Two Sisters Lake. And a beautiful woman's corpse turns up on a snowdrift. Is it payback for a drug deal gone bad? Or is it something more sinister? Osborne and Ferris once again team up to get to the bottom of a very murky mystery.