By Diana Wynne Jones
Greenwillow books, 1993
Hexwood is a young adult novel that is actually science fiction but spends a large portion of the story in a fantasy setting. It does not share a world with any of Dianna Wynne Jones' other books.
The story starts with a bit of bureaucracy. Apparently, there is trouble on Earth, a backwater planet that doesn't even know that they are nominally part of the intergalactic empire. No one pays much attention to Earth, and so no one noticed that the Earth archives at Hexwood are also home to some ancient Reigner technology that could be potentially quite dangerous if anyone was dumb enough to mess about with it. Until Hexwood falls off the map...
The local agencies are a bit slow to respond, but it eventually makes it far enough up the chain of command that someone who knows what is really stored at Hexwood is notified -- and then it goes up right to the top pretty quickly. But not before a good number of theoretically responsible and powerful people rush to Hexwood and mysteriously disappear.
The device in question is essentially a giant computer that solves problems by co-opting anyone and anything around to run simulations of hypothetical situations. Apparently, someone at Hexwood asked it to run a Dungeons and Dragons type game, and it went ahead and co-opted the archive's librarians and locals to start playing out some fully immersive scenarios.
The result is an epic and confusing comedy of errors, in which no one, including the reader, really knows what is going on.
This is a good book, although sometimes perhaps a bit confusing. The narrative is non-linear at times, and the characters change roles and sometimes names without warning. By the end I was having a serious problem keeping track of who was who. This is a pity, because the characters are what make Jones' books so entertaining. I found the core of the story -- a young boy being raised in a medieval forest by a modern day teenage girl, a wizard, and robot -- fun and interesting. The intergalactic politics were somewhat less engaging, although that side of the plot does pick up a bit towards the end of the book. Overall, this is not really Jones' best work, but it is good, and I do recommend you read it if you have read and enjoyed her other works.