Lying in the DeepLying in the Deep

When her boyfriend leaves her for her best friend, Jade joins a semester long cruise program unaware that the two are also onboard, and when her ex-boyfriend is murdered and his new girlfriend goes missing, Jade must dig into her shipmates' lives to find the murderer and clear her name.
After being jilted by her ex-boyfriend and best friend, Jade couldn't be more ready to embark on the adventure of a lifetime: 11 countries in 4 months, all from the luxurious Campus on Board ship. She is happy to wedge an entire globe between her and the people who broke her heart. When Jade discovers the backstabbing couple are also setting sail, her obsession with them festers into a shocking murder. As their friends begin to drop like flies, Jade and her new crush must race to clear her name and find the killer they are trapped at sea with-- before anyone else winds up in body bags. -- adapted from jacket