Milo's mum has laid an Egg, and it's due to hatch at any time. So when Mum has to go on a food-finding expedition, Dad has to look after the Egg. So it's up to Milo to deliver the Penguin Post mail. He delivers parcels of all shapes and sizes to all sorts of animals. As he is delivering the last parcel he realises there's an extra package in the mailbag, one that he needs to get home as quickly as he can...