An investigation set in the aftermath of WWI. Multiple victims, a countdown, a riveting case led by a teenage boy and a journalist.

Who killed Timoleon Escartefigue, the humble bicycle repairman of Boulevard des Batignolles in Paris? What happened on the battlefront during the Great War, in the rubble of a destroyed house? What became of Victor, who was sentenced to death and vanished before his execution? What secret is Emilienne Robinson hiding, the new recruit of the newspaper The Excelsior? And why are veterans being murdered one after the other in 1920s Paris? Who is behind this? Balto, who lives in the Zone, a band of misery encircling France's capital city, sets out on an investigation to prove his brother Victor's innocence. To do so, he'll need to identify the last Jack of Hearts... before it's too late.