Aphrodite (Daughters of Zeus #4)

Being perfect isn’t easy, but Aphrodite is determined to live up to the ideal. So when Poseidon asks her to investigate strange happenings on several cruise ships, she jumps at the chance to prove herself. Demigods are going missing, and no one remembers them having been on board. Aphrodite charms herself into the best room on the ship, prepared to investigate in style. Unfortunately, the room belongs to the one man immune to her charm.
Adonis.
When Aphrodite realizes that he could be the next target, her investigation gets more complicated. Worse, whoever is responsible for the missing demigods charmed the passengers and armed them with long-forgotten weapons designed to kill gods. When the ship goes dark, Aphrodite and Adonis have to work together to discover who is behind the mayhem before Poseidon decides their ship, and every charmed and armed human on it, are more trouble than they’re worth.