Something fishy is going on in Gotham City Harbor! An ancient shark curse has taken a bite out of a whale-watching charity event, and it's up to Mystery Inc. and the Dynamic Duo to dive into danger. Can Scooby and his friends help Batman and Robin reel in an aquatic kingpin, or is the calamitous cruise doomed to the depths of the sea? Find out in this action-packed chapter book for fans of Batman and Scooby-Doo!