In his latest plan to get to the mainland, Moby hijacks the Whale Patroller and pilots it, though he and McSquidly work on mastering it's controls. With the PAW Patrol's vehicles on the Whale Patroller, Coral summons some sea creatures to come to their aid and act as a mode of transportation for them with Robo-Dog being Ryder's mode of transportation.
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.