Overground Underground

Onny goes to the vegetable patch to get some carrots and sees them disappearing into the ground. She goes to Pi to get help. He decides to use his drilling machine to investigate the mystery of the missing carrots, and takes Gully with him. Underground they find a large cavern inhabited by moles, and Gully finds out that they are taking the carrots to help them see in the dark. With the mystery solved, they head back but Pi realises they are stuck because the drilling machine can only go downwards. They discover that the cavern contains magical bouncing mushrooms that they use to bounce up the the hole in the ground made by the drilling machine and they get back overground safely.