The Snorks fix up Corky's sub, and Smallstar gets inside and starts it up. The sub goes haywire and it crashes into the Boo Lagoon where the Skull Castle lays. The Snorks plan to help out, and tricks Junior into going with them when they say that there is a treasure. They meet a ghost, and they think that he was going to eat them. This ghost is a friendly one who was terrorized by the One-Eyed Pirate. They find Smallstar and the key to open the ghost's chains. They help the ghost fing his long lost love, Penelope.