Hearing about the pearls of Puplantis, Mayor Humdinger and the Kitten Catastrophe Crew pilot a mechanical shark to take them to Puplantis. While the Kitten Catastrophe Crew performs a diversion, Mayor Humdinger poses as a mer-pup named Merdinger in order to get close to the giant clam that makes the pearls so that he can get a purple pearl. Coral calls in the PAW Patrol when havoc occurs in Puplantis.