Christmas 1939. In Europe the Phoney War hides carnage to come. In Ireland Detective Inspector Stefan Gillespie keeps tabs on Irishmen joining the British Forces. It's unpleasant work, but when an IRA raid on a military arsenal sends Garda Special Branch in search of guns and explosives, Stefan is soon convinced his boss, Superintendent Terry Gregory, is working for the IRA.

At home for Christmas, Stefan is abruptly called to Laragh, an isolated mountain town. A postman has disappeared, believed killed, and Laragh's Guards are hiding something. Stefan is the nearest Special Branch detective, yet is he only there because Gregory wants him out of the way?

Laragh is close to the lake where Stefan's wife Maeve drowned years earlier, and when events expose a connection between the missing postman and her death, Stefan realises it wasn't an accident, but murder. And it will be a difficult, dangerous journey where Stefan has to finally confront the ghosts of the past not only in the mountains of Wicklow, but in Spain in the aftermath of its bloody Civil War, before he can return to Dublin to find the truth.