Harold Fry has recently retired and now, he doesn't do very much. Even mowing the lawn, like his wife Maureen tells him to do, seems too much work for him. When, one day, he recieves a lettre in a pink envelope, this lazyness changes. In it, his collegue from long time ago, Queenie Hennessy, tells him she is going to die soon from a cancer in a hospice at the other end of England. Harold, at first helpless, decides not only to write her back, but to walk the whole way from Kingsbridge to Berwick-upon-Tweed.

During his walk, he will not only meet a lot of people, listen to their story, but also make a journey into his own past, his relation to both Maureen and Quennie and his son David. He is walking to save Queenie, but is he also saving himself?