To celebrate her 14th birthday Sammy's newly-found, long-lost father takes her and best friend Marissa on a cruise. As Sammy navigates her feelings about this new relationship she and Marissa become involved in another family's bizarre drama which includes the mysterious disappearance of the wealthy matriarch and suspicious activity by the greedy heirs. The seventeenth mystery in the wildly popular series combines exciting high-seas adventure with the touching emotional journey of this irresistible teen sleuth.