Missing his human life, Mae and Bee decide to throw Lionel the frog a proper human birthday party! However, Witch Linda's advice proves to be less than reliable.

After missing their stop, Mae and Bee end up having a sleepover at the Mousetrain's underground house. However, everything being so different soon has Mae thinking of home.

On a shopping trip to Pondland, Mae and Bee embark on a mission to retrieve a lost toy from a mysterious island - but all is not what it seems!