When dependable cat sitter Marley Quinn accepts a dream assignment caring for Sir Percival, the extravagantly spoiled feline of screen icon Celeste Lavigne, she expects ocean views, fussy feeding schedules, and perhaps a little celebrity drama. What she does not expect is Percival’s obsession with a locked passenger cabin—or the diamond bracelet Marley finds hidden inside. The bracelet belongs to a woman reported missing overboard the night before. As the pet-friendly luxury cruise glides between fog-softened coastal ports, Marley follows a trail of lies through champagne brunches, grooming salons, and moonlit promenade decks. Everyone on board seems to be hiding something, and the killer is counting on the sea to swallow the truth. But they forgot one thing: cats notice everything.