Jeremy Wade searches for more water-dwelling beasts. In this edition, he investigates stories of a twenty-foot lake monster that attacks humans in Canada's waterlogged wilderness. These remote backwaters are far too cold and cut-off for either snakes or freshwater sharks, and giant sturgeon are likewise off the suspect list. So what could explain the surprisingly widespread accounts of a large, aggressive beast that rears its reptilian head above the surface? Jeremy's investigation turns into obsession as he tries to track down a shadowy predator with a mouth like a bear-trap.