THERE WAS A FLASH OF LIGHT, THE AIR FLICKERED... AND THE WORLD CHANGED. IT'S MAY 21, 1941, THOUGHT JOHNNY. IT'S WAR.

Mrs Tachyon the bag-lady is not the sort of person you'd normally choose to hang out with. But when Johnny Maxwell and his friends find her semi-conscious in an alley, they have to do something... as long it it's not the kiss of life.

The more time Johnny spends with her, the more he finds that Mrs Tachyon isn't the ranting old nutter everyone thinks she is.

She seems to hold the key to different times, different eras -including the Blackbury Blitz in 1941. Suddenly now isn't the safe place Johnny once though it was, as he finds himself boundup more and more with then. And, as time shifts beneath him, and the shopping mall and TV arials melt into air-raid sirens and ration books, Johnny wonders just how much changing the past can really change the future...

This time-stoppingly funny, richly entertaining new adventure from the master of fantastical and irreverent wit, Terry Pratchett, is the third in the series about Johnny Maxwell, following "Only You Can Save Mankind" and "Johnny and the Dead".