Sarah Lancashire stars in the drama set in a fictional Welsh town where an explosion at a construction site that has killed several teenagers. In the aftermath of the tragedy, Polly worries that husband Iwan might be hiding something. Angela gathers the families to fight for justice, and as Harriet faces questions at work, her assistant - and lover - Tim acts to protect her by leaking information that drives a wedge through the town. Co-starring Mark Lewis Jones, Joanna Scanlan and Sidse Babett Knudsen.