Moby and Coral have always been "enemies" but everything changes when Puplantis is destroyed. Coral and Moby will have to learn to trust each other and understand new emotions that flow through them. But will the Merpups accept these new emotions? And will Puplantis' new enemy return?

The story description for Moby and Coral within this event generally centers on Moby's attempts to disrupt life in the underwater city of Puplantis, with Coral, Skye's long-lost mer-pup cousin, and the other Aqua Pups working to stop him. Coral is a plucky, outgoing mer-pup princess and Skye's long-lost cousin who joins the PAW Patrol to help protect Puplantis and balance her royal duties. She is a dedicated member of the team, using her skills and her connection to the local sea creatures to aid in underwater rescue missions. Moby is the main "baddie" of the Aqua Pups series, an unhappy Portuguese Water Dog mer-pup who yearns for a life on land. He is a technological genius who finds the constant singing and celebrations of the other mer-pups annoying, leading him to devise various schemes (often with his sidekick McSquidly the squid) to disrupt the city's harmony or even float Puplantis to the surface. The main story arc involves Coral and the Aqua Pups working together to foil Moby's plans. Key conflicts include: Saving the Floating Castle: Moby's initial major scheme involves using his inventions to float the entire city of Puplantis to the surface to escape the noise, which the Aqua Pups and Coral must prevent. The Mer-Race: Moby uses traps and cheating to try and win or disrupt the annual mer-race, requiring the pups to intervene. Stealing the Whale Patroller: Moby swipes the Aqua Pups' mobile base, the Whale Patroller, prompting a chase involving the pups and their sea creature friends. Throughout these adventures, Coral often tries to encourage Moby to change his grumpy ways and even rescues him when his own schemes backfire, highlighting themes of teamwork and understanding.

Everest receives a letter from a relative who lives in Russia, and will have to leave for Siberia. Not wanting to go on the trip alone, she'll ask Marshall to accompany her. But when they arrive at their destination, the two will discover the chilling reason why Everest was called.