Billy Parker is fourteen. He has got brown hair, green eyes and a small nose. He has got a sister, too. Her name is Roxanne (but everbody calls her Rox). It is August. Billy and Rox are staying at their grandmother' house in Brighton. One Sunday, Billy looks at his bicycle. It ois very, very old. "I need a new one, " he says. "But the question is how? New bikes are so expensive.