Detective Nicholas Black has cause for concern. He's investigating the suspicious death of a young woman whose body has just washed on shore in full scuba gear. Normally it would simply be a case of drowning, yet along with this particular body is a stolen Vincent van Gogh painting in a watertight tube. To further complicate matters, the phone number of Dr. Dulcinea (Dulcie) Chambers is written on the dead woman's hand. As the new director of the Maine Museum of Art, Dulcie is already busy negotiating the sale of one of the museum's pieces with a wealthy collector. When Dulcie learns that she's a chief suspect however, she has no choice but to help with the investigation. Dulcie finds herself diving in to solve this mystery as her relationship with Detective Nicholas Black also reaches new depths.