Hazel and Robin, retired nuclear scientists, live in a coastal cottage impacted by a radiation disaster at a local power station. Rose, a former colleague, appears at their doorstep after an absence of 38 years. She is not entirely welcome: long-buried secrets threaten to overflow at any moment, and catching up with each others’ lives over the last four decades throws their differences into sharp relief.

As the three spend time together, it becomes clear that Rose has come with a proposition that requires them to consider what they owe to each other, and to their children.