Billy Grimshaw thinks the world of his dad. He hasn't seen him for ages, but Billy knows he'll be home as soon as he can get away from his important spying business in London. In the meantime, Billy is grappling with the disastrous news that his mum is going to marry Dave. As he makes secret plans to stop the wedding, Billy's life gets more and more complicated, not helped by the classroom bully or even his friend, Big Lauren . . .