Kate is building a sand castle, but the windchimes she places on top aren't working. In Mimiloo, after Mim-Mim accidentally ruins a one-of-a-kind music recording, Kate, Mim-Mim and their friends visit the Singing Seas where Callie, a giant octopus, keeps her Mega Music Maker. But it's broken! Kate leads the gang on a quest to fix the island-sized instrument.