When Johnny Maxwell finds himself mysteriously transported through time to the Second World War, he knows when and where bombs will fall. If he tells anyone, he risks changing the future. If he doesn't, innocent people will die. . . .
Old bag lady Mrs. Tachyon is considered nuts but harmless, pushing around an enormous trolley full of bags and a mangy cat. One day she's found unconscious and beaten in a street; after Johnny and his pals have her taken to a hospital, they put her trolley in Johnny's garage for safekeeping. But Johnny soon finds that the trolley has more than garbage -- there's a new newspaper dated from decades ago.
Before you can say "what the disc!", Johnny and his friends (dignified Yo-less, wannabe-nerd Bigmac, abrasive Kristy, and not-so-dignified Wobbler) are whisked back in time to 1941. At first they're intrigued by the weirdness of the old place, but things take a nasty turn: Bigmac is arrested, while Wobbler is first harassed by a bratty kid and then accidently left behind. When Johnny and his pals reappear, they soon discover that their brief trip back in time has completely messed up the timeline...
This book is more complex than "Johnny and the Dead" and better-written than "Only You Can Save Mankind." Pratchett's quirky characters, occasional social commentary and funny speculation (the trouser-legs-of-time description is the best time description you can find). The appearance of the elderly Wobbler is a stroke of genius, as is the "... I'm a Muslim" joke that serves an important part of the plot.
Pratchett's writing is clearer and quirkier here than before. The storyline is far smoother and more detailed, and he puts in extra scenes that add to the characters (such as Yo-less dealing with a '40s woman's racism) without distracting us from the story. And the funnier scenes (like the police interrogaton, or the "spy!" harrassment) are absolutely hysterical.
As before, Johnny is the one really normal person as well as the smartest. Yo-less makes less of an impact unless dealing with stereotypes, and Bigmac makes very little unless being interrogated. The rather self-satisfied Kristy barges undiplomatically at Johnny's side (though she does deal with '40s sexism in a very amusing way), and Wobbler has the subtlest and perhaps most interesting role.
"Johnny and the Bomb" incorporates the strengths of the previous two books, finishing it off with a flourish (and lots of explosions). Funny, cute, a time travel story for the thinking reader.
The characters of Johnny’s remarkable friends are fleshed out in this novel to a much greater extent than they were in the previous two novels. Yo-less, a black kid, is less than pleased to find himself dubbed Sambo by the folks living in 1941, and the extremely forceful young Kirsten is almost as upset about being treated like a “little lady.” Johnny, for his part, often finds himself putting his sanity at risk by contemplating the ways and whims of time travel. I found this book to be hilarious; the time travel part of the tale is a little wild and crazy, but hypotheses about the different legs of the Trousers of Time is vintage Pratchett material. Old Mrs. Tachyon is a wonderful character, seemingly rather insane based on her thought processes and tendency to spout gibberish all the time, she is perhaps more sane than anyone else around her; time traveling is enough to warp anyone’s mind, Johnny reasons. I was rather delighted to hear Mrs. Tachyon mumble the words “Millennium hand and shrimp” at one point because these are the very same words often spoken by Foul Ole Ron on the Discworld. This adventure really is the type of thing you might expect to find on Pratchett’s famous planetary creation, and I daresay any Discworld fan should enjoy this book immensely. I find myself wishing for more Johnny Maxwell stories; I feel as if I know these characters now, and they are a fascinating, increasingly funny bunch of guys to hang around with.