The Marcella II — Eva Pohler

Poseidon calls on Prometheus and his troop of young gods aboard the Marcella II to investigate pirate ships swarming the Mediterranean Sea. Poros, Hestie, and Hermie rush into danger and are taken by surprise by what they soon realize aren't ordinary pirates--they're vampires. The vampire pirates are highly organized, stealing enormous amounts of goods from merchant ships. Hades recruits demigods Gertie and Hector to join forces with those aboard the Marcella II to rescue the young gods and to uncover the secret of the vampire pirate organization. When the identity of the pirates' leader is revealed, the entire pantheon is shocked to its core.