It’s 1978, and Jack Sheffield begins his second year as headmaster of a small village primary school in North Yorkshire. One day, there are three letters on his desk. The first one makes him smile. The second one makes him sad and the third one is going to change his life forever. One of them is from nine year old Sebastian who suffers from leukaemia in the local hospital. He writes a heartbreaking letter addressed to ‘Mister Teacher’. So Jack tries to help. As a result, he begins a journey through the seasons of Yorkshire life in which the school is the natural centre of the community.