Here we have a story that is more than meets the eye. Paris is enmeshed in a soupy fog that gives the morning the appearance of a Gothic evening. Maigret makes his way from his home to police headquarters where a young lady with a modest and mousy demeanor, Mlle. Cécile Pardon, has been dutifully awaiting his arrival. Lately, she had been a frequent visitor to police headquarters, vainly trying to get Maigret's attention about some "irregularities" she had noticed at the apartment of her old and miserly aunt with whom she lives and has dutifully catered to her needs for years.
When finally Maigret deigns to meet with Mlle. Pardon, she is gone."His first reaction was to shrug it off. Then, as he sat down again, he frowned. This was not like Cécile, who had once waited seven hours for him, sitting motionless in the waiting room. There were papers all over his desk. He searched through them for the slip she had filled in. At last, under youong Duchemin's file, he found it.
'I must see you most urgently. Something terrible happened last night.' - Cécile Pardon"
Maigret, now in reflection mode, thinks back several months ago to a meeting he had at police headquarters with Mlle. Pardon in which she told him of her suspicions that someone had been rummaging through her aunt's personal effects during the evening. Someone who has managed somehow to get access to her aunt's apartment at a time in which she and her aunt --- who is a virtual invalid --- are fast asleep. Cécile explained to Maigret that "... not only did I find that two chairs had been moved, but also that the thread had been broken. ... So, obviously someone must have been in the apartment. Whoever it was spent some time in the sitting room and, what's more, opened my aunt's desk. I'd rigged up something there, too. It's the third time in two months. My aunt has been almost wholly incapacitated for some months. No-one has a key to the apartment, and yet the lock hasn't been forced. I haven't liked to mention to Aunt Juliette, it would only worry her. All the same, I'm certain of one thing, nothing has been taken. If it had been, she would have mentioned it; she's so suspicious of everyone."
His curiosity fully aroused, Maigret makes his way to the house in the Bourg-la-Reine neighborhood where Cécile Pardon had lived with her aunt for many years. There Cécile's aunt is found in her apartment, dead. Cause of death: strangulation. A search is then carried out for Cécile, who had been so anxious to speak with Maigret that morning. Eventually she is found in a somewhat obscure corner of police headquarters - dead. Cause of death: murder.
The rest of the novel is centered upon Maigret's efforts to solve both murders, a process which takes him down a winding path involving many of the characters in the house in the Bourg-la-Reine. Never a dull moment here. Any reader need only afford him/herself some leisure and become immersed in this lively, engaging story.