When a new fence is put up, Hedgehog is left trapped in her garden and uses the rubbish she collects to build a hot air balloon. However, her efforts lead her to drop in unexpectedly on the Water Voles, and Grandpa Burdock and Grandma Dandelion must be creative in order to get her home. Notes at the back of the book cover how to make your own garden hedgehog friendly and instructions on how to make a papier-mâché hot air balloon.