Maigret investigates the stabbing in an alley of an unassuming man leading a double life, despised by his wife and family, held in affection by past co-workers and acquaintances. The mystery of how he funded this life forms a principle strand of Maigret's enquiries.
Cold, torrential, late-autumnal rain and humid, overheated rooms infuse the atmosphere, with the inspector brooding ruefully on the "quiet desperation" of the lives he encounters.