Dr. Peña (Esposito), a cryptozoologist, manages to capture El Chupacabra on a remote Caribbean island and smuggles it aboard the cruise ship Regent Queen, commanded by Captain Randolph (Rhys-Davies) with the assistance of his young daughter, and ship fitness instructor, Jenny (Simmons). The Regent Queen has been experiencing a rash of burglaries, and Federal Marshal Lance Thompson (Neal) is brought on board to investigate.