Yuletide Murder at Sea: The Lost Treasure Mystery by Sue A Stewart – Sponsored by Pump Up Your Book. Genre: Cozy Murder Mystery, Sub-genre: Amateur Sleuth. Retired librarian Molly St. Clair sets out on a Christmas cruise expecting relaxation and holiday celebrations with her close-knit group of friends. Instead, the voyage takes a dark turn when a fellow passenger is found dead under suspicious circumstances. Read an excerpt and interview.