A group of teenagers in a Welsh town break into a construction site to make mischief, only for an explosion to claim the lives of several of the children. As the locals struggles to come to terms with the tragedy, one mother directs her anger at the boss of the building project, determined to get justice

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.

The inquest opens and questions are asked of Iwan, Alan and Harriet. Polly is forced to choose between her husband and justice when asked to betray Iwan.

Harriet is in the dock for gross negligence manslaughter as the families' private prosecution finally arrives in court. And Polly fears for Leona, who wants to give evidence.