Within this wonderfully rollicking adventure fantasy there is a very serious theme - that of a little girl missing her mother who has died and of a father who doesn't know how to help her. Mum died when Tilly was six, and now that she has reached the grand age of seven and a half, she thinks she is quite a big girl. However, she isn't too big to know that her happiest day ever was her sixth birthday when mum was still around and to want to go back there. Dad, a mad scientist, is very loving to Tilly, but he is also so busy with his invention of a time machine that he doesn't realise Tilly's problems - and he has his own difficulties dealing with his wife's death. The two of them don't really communicate much and never about mum. When Tilly wakes up one morning to find dad has disappeared, it isn't long before she works out that he has gone back in his not-very-trustworthy time machine and has got lost somewhere in the process. The following pages are a super mishmash of Tilly's thwarting a couple of comic thieves who are out to steal the machine, her operating the machine to look for her dad and finding along the way that she is in the middle of the Battle of Trafalgar with Nelson, then in the famous 1966 football game with Germany, going up a chimney in Victorian times and having tea with Queen Victoria (who is understanding about how much she misses her mum) and, finally, in her own kitchen with dad and mum on her sixth birthday. There is closure for them all in this encounter, and both dad and Tilly realise that they need to have lots of pictures of mum about and to be able to talk about their happy memories of her. There is a great deal of humour in the story, but also lots of realistic feelings about death and missing someone you love, and the wacky ink-based illustrations on almost every page, along with quite a lot of integrated text, make the book easily read even though it's a long novel at 223 pages. A good combination of the serious and the definitely not!