On the evening that Lydia Cunningham drives to the train station to meet her daughter Thelma, the pretty little coastal town of Milton St Gabriel is sleeping quietly. The town's utter normality is reflected in Lydia, a respectable widow of advanced years.

But Thelma's arrival will shatter the peace of Milton St Gabriel forever. Thelma brings with her Edward, a young and not altogether appealing casual pick-up with a penchant for arson, and the two of them unleash events that reveal a sordid and long-hidden tale of illegitimacy and death. But this is only the groundwork for what lies ahead as Lydia, encountering her past, falls over the edge of sanity into a nightmarish world of revenge and murder.