“Harold” (Jim Broadbent) is having breakfast with his wife “Maureen” (Dame Penelope Wilton) when he opens a letter. It turns out to be from a colleague from the brewery in which he worked and it mentions that she is in an hospice, terminally ill with cancer. He pens the briefest of replies and sets off to post the letter. En route, he pops into the local garage for a pint of milk and encounters a young girl with blue hair (Nina Singh) who urges him not to lose hope. Her words have quite an effect. He decides to post his letter in the next post box, then the next. The next thing we know he in on a trek some 450-odd miles from their home in Devon to Berwick-upon-Tweed. That’s about as far as he can actually walk without entering Scotland! Along the way he encounters some interesting characters whilst fighting a bit of a rear guard action with his bewildered wife at home (via the phone) and we are also, gradually, introduced to flashbacks illustrating the tragedy both went through with their own increasingly wayward son “David” (Earl Cave).