Oxford Bookworms Library 1: The Piano Man

A woman finds a man on a beach. He is very cold, his clothes are wet, and he cannot speak. The woman phones for help, and an ambulance comes and takes the man to hospital.
 In hospital they ask the man questions, but he does not answer. He still cannot speak - or does not want to speak. Who is he, this strange man from the sea? What is his name? Where did he come from? And why do they call him the Piano Man?