Michael Tanner and his wife, Mary Whitney, are temporarily deprived of their yacht Sea Queen, normally harbored on Puget Sound. A telephone call from Ashland, Wisconsin, alters their summer plans. Tanner's PR firm is engaged to develop a marketing plan for a company that is harvesting ancient timber from the bottom of Lake Superior. Mary, an avid sailor, accompanies her husband to Wisconsin and is seduced by the lake. During recovery operations an old skull with a bullet hole is raised, and an environmental activist is found murdered in the company's warehouse. Circumstances spiral further down, entangling Tanner and Mary who must fend off accusations and dodge several murder attempts before the cases are solved.