Catboy realizes being the best isn't always the solution when the PJ Masks have to prevent Night Ninja from stealing a magical ring hidden atop the Mystery Mountain. Catboy, Gekko, and Owlette have to get into the Mystery Mountain to retrieve a magical ring for Night Ninja, who captured PJ Robot. As Rip and Howler are tagging the city with paint, Kevin starts to have second thoughts about being a mean one.