Natural Flights of the Human Mind by Clare Morrall

Peter Straker lives in a converted lighthouse on the Devon coast with a fine view of the sea, two cats, and no neighbors. That's just the way he likes it. He speaks to no one except in his dreams, where he converses with some of the seventy-eight people he believes he killed nearly a quarter-century earlier -- though he can't quite remember how it happened. But Straker's carefully preserved solitude is about to be invaded by Imogen Doody, a prickly and unapproachable school caretaker with a painful history herself. Against his will -- and hers -- Straker soon finds himself helping Imogen repair the run-down cottage she's inherited. There are forces gathering, however, as the twenty-fifth anniversary of Straker's crime approaches, and they're intent upon disturbing his precarious peace.