Monica, daughter of Morton Sampson, the president of Fiesta Cruise Lines, is living under a false identity in the Florida Keys, in an effort to escape her father. When Butler Jack, a shady figure from her childhood, offers Monica the chance to avenge her mother and humiliate her father, she jumps at it, without realising his true motives.
Jack takes the Eclipse hostage on its twenty-fifth anniversary voyage, and begins to kill off the passengers and crew one by one. Monica unwillingly holds the ship's fate in her hands, while her own fate becomes ever more uncertain...