Tide Of Terror Vampirates Series, Book 2.

In this sequel to Vampirates: Demons of the Ocean, there's a traitor aboard the Diablo and enemies at every turn. As the danger intensifies, Grace discovers a place where her twin brother Connor could learn more about the pirate way without risking his life: the elite Pirate Academy. Will Connor choose an education by sea or by school, and will Grace be forced to follow him wherever he goes?