Traitor Isle (The Memory Chase Trilogy #3)
Laurie Sanford

Married at last to Gabriel Clement, Madeleine never dreams that anything will separate them. But on a trip to Rome for Carnevale, a mysterious man re-enters her life and unearths secrets that threaten her newfound happiness.
Running from her pain, she boards a ship bound for the last place she ever expects—an island that once imprisoned her. Madeleine soon finds herself alone amid a group of sailors on the hunt for lost treasure. In a struggle to survive and remain hidden, she vows to find the treasure before her enemies. But what can heal her shattered heart and lead her back to grace?