Sandy is finally old enough to join Grug and Eep for the annual Daddy Daughter Day and Grug couldn't be more excited. But when Sandy struggles to fit in with Grug and Eep's traditions, Grug has second thoughts.

When Gran announces it's time to choose a new Thunder Sisters Queen, Ugga assumes she's got it in the bag. But after a series of challenges (the Thunder Games), it becomes clear Gran might not be ready to step down.