This is the story of Roo, a little dinosaur who one day meets a woolly mammoth in a hot-air balloon. The balloon has a hole and gradually deflates, floating down to the ground and leaving the little mammoth stranded. Roo saves the day by giving the mammoth a piece of his precious comfort blanket (his moomie, as he calls it) which they use to patch the hole.

A story about kindness and sharing, with lovable characters created by the best-selling illustrator of the Lettice the Dancing Rabbit series, Mandy Stanley.