When Mercedes Mackaill has a month off work in which to house and dog sit at a waterfront home, she soon finds that too much of her own company palls. Then the body of an old woman is pulled from the water in front of where she's staying and Mercedes discovers she'd talked to the woman just days before the drowning. An unexpected meeting with Dorsey Finch, the victim's tenant, leads to discovering the woman's strange past—a story reaching back to 1940s Hollywood and a well-known house on Nob Hill in San Francisco.