After everything Clare and her NYPD detective boyfriend have been through, they deserve a little bit of happily ever after. But while Mike's marriage proposal to Clare is steeped in perfection, the celebration of their engagement is not long lived.

First, a grim-faced attorney interrupts their party with a mysterious letter bequeathing a hidden treasure to Clare's daughter. Next, the world-famous jeweler who designed Clare's ring is found poisoned in his shop. Both events appear to be connected to a cold case murder involving a sunken ship, an Italian curse, a charming jewel thief, and a shocking family secret. With deadly trouble brewing, Clare must track down clues in some of New York's most secret places before an old vendetta produces fresh corpses.