January 1921. Though the Great War is over, in Ireland a new civil war is raging. The once-grand Kilcolgan House, a crumbling bastion shrouded in sea mist, lies half empty and filled with ghosts, both real and imagined, while it shelters the surviving members of the Prendeville family. Then, when an IRA ambush goes terribly wrong, Maud Prendeville, Lord Kilcolgan's eldest daughter, is killed, leaving the family reeling. Yet the IRA column behind the attack insists they left her alive, that someone else must be responsible for her terrible fate. Captain Tom Harkin, an IRA intelligence officer and Maud's former fiancé, is sent to investigate. He becomes an unwelcome guest in this strange, gloomy household.

Working undercover, Harkin must delve into the house's secrets--and discover where, in this fractured, embattled town, allegiances truly lie. But Harkin too is haunted by the ghosts of the past and by his terrible experiences on the battlefields. Can he find the truth about Maud's death before the past--and his strange, unnerving surroundings--overwhelm him?

The Winter Guest is a gripping and immersive read for fans of classic mysteries by the likes of Agatha Christie and Dorothy Sayers along with Charles Todd's Ian Rutledge series, Ann Cleeves, and Jacqueline Winspear.