A call for help from a former colleague leads Maine game warden investigator Mike Bowditch and his girlfriend Stacey Stevens on a sea kayaking trip to a research station far off the coast. Stacey spent summers interning on the island, a sanctuary for endangered seabirds, and they are shocked by the atmosphere of tension they encounter when they come ashore. The biologists are being threatened and stalked by a mysterious boatman who they suspect is trespassing on the refuge late at night. And now the sanctuary’s enigmatic founder, whose mind has been slowly unraveling, has gone missing.