My Brother Is a Superhero - Winner of the Waterstones Children's Book Prize

Luke shares a treehouse with his geeky older brother, Zack. Luke goes for a wee and while he's gone an alien gives his undeserving, never-read-a-comic-in-his-life brother superpowers, and then tells him to save the universe! Luke is furious, but when Zack is kidnapped by his arch-nemesis, it's up to Luke and his friends to save the world.