Dead Letters by David Manning
Labor Day 1989: Duncan Twist’s sleazy client, Nick Varnish, has loaned him a cottage overlooking the salt marshes of Dusktide Beach, a barrier island in southeast North Carolina. Just to the south lies Lorn Island, which is deserted, except for one ethereal resident: the Kindred Spirit. Duncan accidentally encounters a former lover, Tendency Specter, who introduces him to the Kindred Spirit. In turn, the Kindred Spirit introduces him to an unnamed person who has mysteriously disappeared. Intrigued as much by their rekindling relationship as they are by the missing person, Duncan and Tendency begin investigating. As they grapple with both the growing mystery and each other, curious events continue to interrupt both interests. A skeleton half-buried in the sand seems to indicate murder. . . or maybe not. Or are there two skeletons? Is the skeleton a murder victim or has it been there since the Civil War? Only the Kindred Spirit knows the answers, and it’s not talking.