Lucy Gannon (Soldier, Soldier, Bramwell, Trip Trap) has written Dad, the poignant story of Larry James (Richard Briers), a cheery and independent 86-year-old who has been caring single-handedly for his beloved wife Jeannie James (Jean Heywood) who has Alzheimer's disease. When Larry falls and breaks an ankle his life with Jeannie abruptly changes forever. Jeannie is moved into residential care and Larry goes to stay with his son Oliver (Kevin Whately), his daughter-in-law Sandy (Sinead Cusack) and their teenage daughter Millie (Hannah Daniel). But love and consideration wear thin as father and son have to learn to live together all over again.