Empire of Night

Read Empire of Night Storyline:

After the surprising revelation of the Tempest family history, twins Connor and Grace face a newly-defined future marked by their Vampirate roots. Meanwhile, Sidorio's evil Vampirate Empire continues its expansion, making it tragically apparent that no ship is safe. As for the pirates, they have a new mission: wipe out the vampirates.
There's a bloody battle brewing in the seas, and each crew will need all hands on deck. And, this time, Grace and Connor may find themselves fighting for their lives-or against each other.