Unsettled by the recent death of his mother, Paul sets out in search of Pia, his daughter from his first marriage, who has disappeared into the labyrinth of London. Discovering her pregnant and living illegally in a run-down council flat with a pair of Polish siblings, Paul is entranced by Pia’s excitement at living on the edge. Abandoning his second wife and their children in Wales, he joins her to begin a new life in the heart of London.

Cora, meanwhile, is running in the opposite direction, back to Cardiff, to the house she has inherited from her parents. She is escaping her marriage, and the constrictions and disappointments of her life in London. But there is a deeper reason why she cannot stay with her decent Civil Service husband --- the aftershocks of which she hasn’t fully come to terms with herself.

Connecting both stories is the London train, and a chance meeting that will have immediate and far-reaching consequences for both Paul and Cora.