Calder White lives in the cold, clear waters of Lake Superior, the only brother in a family of murderous mermaids. To survive, Calder and his sisters prey on humans, killing them to absorb their energy. But this summer the underwater clan targets Jason Hancock out of pure revenge. They blame Hancock for their mother's death and have been waiting a long time for him to return to his family's homestead on the lake. Hancock has a fear of water, so to lure him in, Calder sets out to seduce Hancock's daughter, Lily. Easy enough—especially as Calder has lots of practice using his irresistible good looks and charm on ususpecting girls. Only this time Calder screws everything up: he falls for Lily—just as Lily starts to suspect that there's more to the monsters-in-the-lake legends than she ever imagined. And just as his sisters are losing patience with him.