Three boys, two grandpas, a tree, a map and some hidden treasure... Let the adventure begin. 11-year-old Nicholas Funes knows he's weird. He plays the violin far too well to be cool, he collects square roots and prime numbers and, weirdest of all, he talks to a tree who he believes is his brother. Plus, he doesn't have all that many friends. But even he is about to struggle with how strange his life is about to get. His long-lost and never spoken-about Grandfather Rose turns up on Nicolas's doorstep one day, fresh out of a lifetime's prison sentence and suffering from dementia...