The Merlin Conspiracy by Diana Wynne Jones

Roddy Hyde lives in an alternative world called Blest. It's much like the UK, the road are terrible and there's no trains, but it's a slightly different shape. Oh, and magic exists. Which is fine, until the wrong people begin to manipulate it and Roddy and her small sidekick Grundo are the only ones to notice. As the magic of Blest begins to unravel and their loved ones start disappearing, Roddy and Grundo are forced to call in some help.

Nick Mallory is stuck on plain old earth but is desperate to escape and explore other worlds. After all that longing, when he's suddenly whisked away it feels like a dream. Within a few hours it turns nightmarish as he's threatened by a hugely powerful wizard, stalked by a Panther, chased by police and bothered by a starving goat. 

Then Nick meets Roddy. Which is good because she's a bit of a looker, but bad because she wants him to help her save Blest. Having hoped for some more experienced help, Roddy resigns herself to working alongside Nick. It would just really help matters if Nick could just work out how to get to Blest...

Diana Wynne Jones is such a talented storyteller that she immerses you in these alternative worlds from the word go. Nick and Roddy's monologues are distinct, but are woven together effortlessly as The Merlin Conspiracy progresses. It's a long novel for a children's book, but there's enough action to keep a keen reader enthralled. The main characters are cleverly drawn with authentic voices. They don't always get on, but they're not constantly at each others throats. It felt real to me, with the gentle tension of a long family holiday. It's just one of the ways in which Diana Wynne Jones' ambling pace pays off.

Nick, Roddy and their unlikely band of followers have a hard task ahead of them in saving Blest, with only a small handful of adults to help them. With good on their side, and The Merlin Conspiracy being a children's book, the reader has a sneaky suspicion that they'll succeed. Diana Wynne Jones skilfully keeps the suspense alive, despite avoiding the temptation to throw in the multiple, sudden plot changes of a Sophie McKenzie novel. The intelligently elaborate plot will charm adult and children magicians alike.