It's 1978 & Jack Sheffield begins his second year as headmaster of a small village primary school in North Yorkshire. There are three letter on his desk
- one makes him smile one makes him sad & one is destined to change his life forever. This is from nine-year-old Sebastian suffering from leukaemia in the local hospital who writes a heartbreaking letter addressed to ' Mister Teacher'. Jack tries to help & so begins a journey through the seasons of Yorkshire life in which the school is the natural centre of the community. There's a colourful cast of characters who accompany Jack through the ups & downs of the school year including Vera the school secretary who worships Margaret Thatcher & whose greatest ambition is to become President of the Women's Institute; Ruby the 20-stone caretaker who sings like Julie Andrews; & Dorothy the coffee shop assistant who is desperate to be Wonder Woman. 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.