It's 1978, and as Jack Sheffield begins his second year as headmaster of a small Yorkshire primary school there is a letter on his desk from nine-year-old Sebastian, suffering from leukaemia in the local hospital, who writes a heartbreaking letter to 'Mister Teacher'. So begins another year in the life of the school and community, in which Jack is accompanied by many colourful characters, including Vera, the school secretary whose greatest ambition is to be President of the Women's Institute, and of course, Beth Henderson, a teacher from a nearby school who with her sister Laura presents Jack with an unexpected dilemma.