Great Aunt Minty seems the wrong person to look after nine-year-old Olivia and her demanding five-year-old sister, Nellie, in the wake of their mother's death. She's white-haired and creaky, and knows almost nothing about children. All she knows about is her big horse-shoe-shaped garden, which is so wild and overgrown, the sisters try to avoid it! Then a mysterious blue teacup turns up in the dirt, and Olivia finds an old story about a party of children transformed into flowers by a fairy spell. Only someone discovering the lost children's eight cups can bring them back. Now, the two sisters know what they must do.