Fred Marche

The rise of a crooked employee of a bank and the attempt of a former co-worker to bring him down.

Théodore Beudraves works at night in a hotel and sleeps during the day. His salary allows him (unbeknownst to his wife Rose) to pay for singing lessons to Gaby Beauchamp, his young friend. But she falls in love with her son, Darius Beudraves, and vice versa.

Poorly educated by her father, a wacky researcher, Claudine is a teenager full of life who loves her small village school run by Miss Sergeant. A new teacher, Aimée Lanthenay, arrives at the school. Seemingly awkward, she is actually an arrivist who manages to get the departure of Miss Sergeant.

A woman's marriage is on the rocks ; to avenge herself, she decides to take a lover for one night .So she buys all his stock from a balloon man and flies them through the Parisian sky ; all her balloons carry a message :"I will be alone after midnight" (hence the title); a lot a suitors comme to the rendezvous : a fisherman, a soldier, a traveler , a gentleman cambrioleur (a nod to Arsène Lupin?) and others ,much to Michel, a young man in love with her's displeasure.

Maigret investigates in Concarneau where the passage of a yellow dog accompanies a series of murders, sowing terror in the population. The police seem helpless. It must be said that it has no significant evidence.