Conor and Grace are twins, recently orphaned after their widowed father's death. Rather than being adopted by the town's busy-bodies, they decide to set sail in their father's last possession, his sailing boat. But a vicious storm sees their boat capsize and the twins are separated. Two mysterious ships sail to their rescue - each picking up one twin before disappearing into the mist. Conor wakes to find himself on a pirate ship and is soon being trained up with a cutlass. Meanwhile Grace finds herself locked in a darkened room, as the vampirates wait for night to fall and their feasting to begin... Determined to find each other, yet intrigued by their new shipmates, the twins are about to embark on the biggest adventure of their lives...