Rhys Gravenor, Great War veteran and Welsh sheep farmer, arrives in Paris in the midst of the city's liberation with a worn letter in his pocket that may have arrived years too late. As he follows the footsteps of his missing son across an unfamiliar, war-torn country, he struggles to come to terms with the incident that drove a wedge between the two of them.

Joined by Charlotte Dubois, an American ambulance driver with secrets of her own, Rhys discovers that even as liberation sweeps across France, the war is far from over. And his personal war has only begun as he is haunted by memories of previous battles and hampered at every turn by danger and betrayal. In a race against time and the war, Rhys follows his son's trail from Paris to the perilous streets of Vichy to the starving mobs in Lyon to the treacherous Alps. But he is not the only one searching for his son. In a race of his own, a relentless enemy stalks him across the country and will stop at nothing to find the young man first.

The country is in tatters, no one is trustworthy, and Rhys must unravel the mystery of his son's wartime actions in the desperate hope of finding him before it's too late - too late to mend the frayed bond between them, too late to beg his forgiveness, too late to bring him home alive.