It's 1978, and Jack Sheffield is beginning his second year as headmaster of a small village primary school in North Yorkshire. There are three letters on his desk – one makes him smile, one makes him sad and one is destined to change his life for ever. This is from nine-year-old Sebastian, suffering from leukaemia in the local hospital, who writes a heartbreaking letter addressed to 'Mister Teacher'. So begins a journey through the seasons of Yorkshire life in which the school is the natural centre of the community. Vera, the school secretary who worships Margaret Thatcher and whose greatest ambition is to become President of the Women's Institute; Ruby, the twenty-stone caretaker who sings like Julie Andrews; Dorothy, the coffee shop assistant who is desperate to be Wonder Woman; all these , and many more colourful characters, accompany Jack through the ups and downs of the school year. Most of all, there is the lovely Beth Henderson, a teacher from a nearby school, who with her sister Laura presents Jack with an unexpected dilemma.