Set in the in the atmospheric and squalid streets of Paris, Maigret sets out to prove the innocence of a man condemned to death for a brutal murder. In another one of Maigret's unconventional and audacious plans, he arranges the escape of the condemned man in an attempt to prove his theory. The presumed murderer goes on the run across Paris and its suburbs, dropping misleading clues along the way and leading Maigret into the labyrinthine twists of the mystery. Maigret is in for more than he bargained for, as he encounters rich American expatriates, dangerous foreigners and their hidden motives.