David agrees to transport a mysterious package aboard a cruise ship. Inside, he discovers an adorable baby Marsupilami — a rare creature with the astonishing secret of eternal youth. Cunning poachers soon begin hunting the unique animal, and David and his family must step in to protect their tiny passenger. The heroes are swept into thrilling adventures and peril on the open sea, where they must show courage to save their new friend from his pursuers and return him safely home.