Denali Hawthorne is a lucky girl. Thanks to a generous aunt, she gets to travel far from the icy Alaska winter to spend spring break on a Hawaiian cruise ship, the Hawaiian Paradise. Denali and her aunt have a wonderful time exploring the islands, and on the ship Denali even runs into an old friend, Gwen. But when Gwen is accused of a crime, Denali is driven to investigate. While most of the passengers relax by the pool, Denali uncovers some strange and suspicious activities. Will Gwen drown under the accusation, or can Denali throw her a life preserver before the end of the cruise?