During the Second World War, a group of youth in the Northeast England town of Garmouth regularly suffer from bomb attacks by the German forces. One of the children raids a crashed German aircraft and takes a fully operational machine gun, intending to set up their own fortress. Playing with it causes a German plane to crash-land; the kids befriend the pilot, who is unaware that they had caused him to crash.

When Dorset postman Clive Peacock is forced into early retirement, the years ahead look bleak. But on his last day in the job, in a moment of unexpected rebellion he makes a decision that will change his life. As he makes his final collection from the postbox in the small seaside town where he lives, he decides to deliver the letters himself, by hand, no matter the destination. Mounting his trusty bicycle, he sets off on what proves to be an odyssey of self-discovery. Pursued by the police and lionised by the media, Clive becomes both a fugitive and a reluctant hero.