Terry Pratchett is probably most famous for writing the now 37-long book series The Discworld, which includes such gems as Small Gods, Men at Arms, Hogfather and Nightwatch. He has also co-authored the wonderful Good Omens with Neil Gaiman.
Nation is not set in the Discworld. It is set in a world not that dissimilar to our own. In the Great Southern Pelagic Oceans, on a tiny island of the Mothering Sunday Islands - so tiny, in fact, that it doesn't appear on any naval chart - lies the Nation. Mau is on his way home from the Boys' Island, and when he returns to the Nation there will be a great ceremony and a big feast, and the sharp thing with the knife where you didn't scream - and then he will be a man.
Paddling home in his selfmade canoe, Mau is caught up in an enormous wave. When he makes it back to the Nation, he is the only one left. Now he is neither man nor boy (perhaps a demon ate his soul), the Grandfathers are constantly shouting in his head, and the only other living person on the island is a strange trouserman ghost-girl.
Ermintrude is a young lady, completely unaware that on the other side of the world, a terrible plague has killed the King and one hundred and thirty-seven other people, and her father is now king. She was on her way to meet her father, the governor of Port Meria (himself completely unaware that he know happens to be King), when the ship she was on was caught in the tidal wave which destroyed the Nation. She, and a terribly foul-mouthed parrot, are the only survivors on the Sweet Judy.
Mau is puzzled by the mysterious trouserman ghost girl. Ermintrude, who much prefers to be called Daphne, was brought up well, but has no idea what the etiquette for receiving a loincloth-clad savage to afternoon tea is, especially when the only chaperone she has is the dead Captain Roberts. Neither speaks the other's language, and there is great confusion.
Nation may well be one of the best books Pratchett has ever written, and it is likely to be one of his last ones, as he has now been tragically stricken with Alzheimer's. It's a novel about identity, about belonging, about questioning the Gods and about surviving. It's not as laugh-out-loud funny as some of his earlier novels, but explores difficult and important themes in an excellent young adult novel, that readers of pretty much any age should be able to enjoy.