The Mennyms, a family of rag dolls, mysteriously given life and personalities by their creator, the deceased Kate Penshaw, has lived peaceably for 40 years in Kate's home in Brocklehurst Grove. Now the Mennyms are being threatened by a proposed motorway that may take their house and others in the Grove. This crisis prompts Kate's ghost to appear to her great-nephew, Albert Pond, asking him to intervene on their behalf. The Mennyms are forced to relocate, and while they struggle to adjust to new surroundings, they face the fear of discovery by the outside world.