Along with everything that she left to her, Fenella’s aunt Mona left instructions for her own birthday party. Doncan Quayle, Fenella’s advocate, is in charge of arranging the party, following Mona’s detailed plans. He gets a little sidetracked, however, when a woman turns up on the island claiming to be Maxwell Martin’s daughter.

Max had been Mona’s benefactor for most of her life. He’d showered Mona with gifts, and now Rosemary Ballard is demanding a share of Mona’s estate. She claims to have letters that prove that Mona had blackmailed Max for years. When Rosemary turns up dead, Fenella is the number-one suspect.

Inspector Daniel Robinson has to keep Fenella at arm’s length, no matter how he feels about her. As Rosemary’s family threaten to continue with the planned lawsuit, Fenella finds herself trying to prove her innocence in the murder investigation, and to find evidence that Rosemary was lying about her parentage.

Mona, Fenella's ghostly roommate in her luxury apartment, is insistent that the letters are fake. As she reveals more to Fenella about her relationship with Max, Fenella works to find a way to protect her fortune and find a killer.

Is it possible that Mona badly misjudged Max? Who else besides Fenella had a motive for wanting Rosemary dead? Mona is sure that Max’s sister is behind the whole thing, but proving that might be an impossible task. As Mona’s birthday party gets closer, Fenella begins to wonder if there is actually going to be anything to celebrate.