Carl Matthews (David Morrissey) commutes by train to London, he has a kind and supportive wife Maggie (Olivia Colman) and two teenage children. One morning he complains to a woman - Sally (Sheridan Smith) - that she has taken his seat on the train. A relationship develops and end up spending more time together.

Adrian Johnston, a long time friend of the studios, composed the music that was recorded and mixed by Steve Price.