Dan and Ally love visiting their Auntie Billie. She is always inventing brilliant things in her garden shed. But one day she doesn't come out, so they go to look for her - and that's when they discover her greatest invention - a time-spray that sends everything back to its natural state.
Used availability for Judy Allen's Aunt Billie's Greatest Invention
November 1997 : UK Hardback
May 1998 : UK Paperback