When a body is recovered from Lake Superior by the Red Cliff Tribal Police, retired Madison Police Detective Molders is asked to help with the investigation. Molders only has a few days before he has to report for a coveted summer job as a Law Enforcement Ranger at Isle Royale National Park. He helps with the initial investigation but has to leave before the victim is even identified.After a 29 year police career, Molders sold his house and now lives aboard his 31 foot Gozzard sailboat. He sails from Red Cliff to Mott Island, the Park Headquarters at Isle Royale.Reporting for duty, Molders is paired up with fellow LE Ranger Katelynn Tomaczeski. Currently a college student, Tomaczeski was born and raised in the U.P. and comes from a long line of commercial fisherman. She thinks Molders is too old to be up to the physical demands of the job and she finds his historical anecdotes boring. Molders thinks she is immature, and too young to know anything. Working together through various park incidents they earn each other's respect and bond as a team.When a second body is found floating in the lake, Molders suspects they have a serial killer and likely more victims. While continuing their daily patrols of the park Molders and Tomaczeski investigate the murders. Their investigation uncovers political corruption, human trafficking, and a serial killer. Together they battle brutal Lake Superior, a dirty cop, and political interference.