Swept into the bright hustle and bustle of New York, Lily, Robert, and Malkin discover shadowy secrets lie beneath its surface. For there are chilling goings-on in their hotel. A strange boy held captive, haunted by an undersea mystery; and a revengeful villain with a treacherous plan. Searching for clues, Robert and Lily are plunged into deep water. But can they reveal the deadly truth before the secrets submerge them?