Pirate queen Valentina Mallozzi kidnaps civilian Miss Gloria Vane for ransom at the nearest port, but Gloria isn't the helpless girl she pretends to be-she's a talented pickpocket and observant spy. Her best chance of escape lies in seducing Mallozzi, but the famed Queen O'Nine Tails won't be wooed so easily.
When a demon sneaks aboard the ship, jumping from body to body in an attempt to gain power amid the chaos, Gloria's situation goes from bad to much, much worse. The remaining crew must find and kill the demon while juggling an increasingly paranoid and out-of-control Mallozzi, whose foretold destiny threatens to destroy them all.