Quick recap
August 1914. Paul Delroze marries Élisabeth and finds that the woman in an old portrait from her family seems tied to his father's murder years earlier. Soon World War I breaks out, the Germans invade northern France and Élisabeth is trapped at her family's château on the occupied side. Paul heads to the front and turns the war into a personal investigation, chasing the truth about the murder and a planted spy. Lupin barely appears, in a part added later. The book is more war and spy novel than heist story.
