The murder of an innocent shakes Ireland to its core. Garda Mary Shea is given the rare opportunity to do some real police work in a quest to find the answers.

One cold January morning in 1980, on a beach in Kerry, the body of a newborn baby is found in its most sheltered sand dune. When local police are called to the incident, Garda Mary Shea is first on scene.

The Dublin major crimes team are called to investigate and because Mary is able to get crucial, female witnesses to cooperate, lead detective Matt Foley takes her under his wing in his bid to solve the biggest case of his career. More questions than answers are found when it becomes clear many locals conduct secret lives — but who would do such a thing?