Jewels from the Sea — Cassandra Pierce

Heiress Savannah Godfrey is relaxing on the deck of a Caribbean cruise ship when a gorgeous naked man rises from the water and invites her to the island retreat he shares with four other mermen. Together, Kral, Bariah, Joquin, Jhoad and Zoeb introduce Savannah to a world of sand, surf, and bodily pleasures she has never imagined. Savannah is astonished, but intrigued, when the mermen suggest that she is the perfect mate for all five of them, an arrangement central to traditional merman culture. She returns to the ship to consider their offer, but before long a mysterious attempt is made on her life. After they rescue her, all five mermen pledge to help discover and outwit whoever is trying to kill her. Will she live long enough to take them up on their offer of a multiple marriage?