The novel begins with a description of a small haberdashery shop in the Paris passage, which contains Theresa Raken and her aunt of about 60, Ms. Raken. They live in the same building, on the upper floors.

Before, Ms. Raken traded haberdashery in Vernon, but after her husband's death, she closed the case and led the life of a hermit: she rented a house on the banks of the Seine, where she spent all her time with her son Camille and niece Teresa.

Camille all his childhood was a sickly child, but his mother still won him over from death. Because of his painful childhood, Camille was short, puny and frail. He also could not learn, and remained an ignoramus.

Teresa was brought from Algeria by Captain Degan, Ms. Raken's brother. She was two years younger than Camille. Her mother, a native, died. The girl was recorded in the name of Degan, and he gave it to his sister, Mrs. Raken, for education. Teresa was surrounded by care, and grew up a healthy girl, but she was looked after as well as the sick Camille. She even drank his medicine. All this made her too obedient and even indifferent.

Soon Teresa and Camill got married. That this will happen, they knew from childhood. Therefore, it did not bring any changes in their lives: after the first night that the newlyweds spend together, Camille "is still painfully languid."

After the wedding, Camille resolutely declared that he intended to settle in Paris. So the whole family settled in the Pont Nef Passage and Ms. Raken again opened a haberdashery shop in which she traded with Theresa. Camille received a position in the management of the Orleans Railway. Once a week, on Thursdays, the family received guests. They were visited by an old acquaintance of Mrs. Raken, police commissar Michaud with his son Olivier, and old Mane, who worked with Camille.

Once Camill brought his former classmate Laurent to the house. It turned out that Laurent also serves in the management of the Orleans Railway. Laurent's father wanted his son to become a lawyer, but Laurent, a loafer, walked with friends instead of classes. For some time he tried to do painting, but nothing came of it. Laurent had to find a job. From this evening he became a regular Thursday guest at the Rakenov.

Laurent began to paint a portrait of Camille, therefore he often visited his apartment. Gradually, Laurent and Teresa became lovers. Laurent had vested interests; he wanted to take possession of Theresa's money. Dating lovers took place at the Rakenov, right in their conjugal bedroom. Soon they began to realize that Camill was only bothering them. Laurent had the idea of ​​killing him.

Once the three of them went boating on the Seine. Laurent threw Camille overboard. Camille resisted and even bit Laurent by the neck, but still Laurent got his way: Camille drowned. Everything was arranged as if the boat overturned, and Laurent, saving Teresa, did not have time to help a friend.

At first, Ms. Raken was very grieved over the death of her son, but soon life went back on track, although Thursday meetings did not even stop. A year later, Teresa and Laurent decided to get married. They made it so that the idea of ​​their marriage was first expressed aloud by Ms. Raken and her guests.

Soon, the newlyweds begin to understand that they cannot be together: they always see Camille's corpse. The scar on Laurent's neck, left by the resisting Camille, has not healed and is constantly bothering Theresa's new husband. Even in bed, the newlyweds think that between them lies the body of the drowned man.

Laurent again became interested in painting, but all the portraits of his brush are similar to each other. Soon, Laurent realized that all his drawings, even drawings of animals, looked like a drowned man Camille. The relationship between Theresa and Laurent becomes unbearable ... Often Laurent beats his wife.

Ms. Raken broke paralysis, gradually she stopped moving and even talking. From the conversations of her niece and her husband, she suddenly realized that they were the murderers of her son. This terrified her. Soon, Theresa and Laurent began talking about Camille's murder, unashamed of Ms. Raken's presence. Once, at a traditional Thursday party, the old woman gathered all her strength, attracted the attention of the guests and put a finger on the table: “Teresa and Laurent at ...”, but did not manage to finish the most important word. the forces left her, and the guests decided that she wanted to write: "Teresa and Laurent surprisingly care about me."

Teresa tried to repent. For days on end, she begged the old woman for forgiveness, but soon went into debauchery. Theresa and Laurent did not trust each other. They were afraid that one of them would tell everything to the police. Both decided on a new murder. Laurent bought a vial of potassium cyanide, and Teresa sharpened the knife. Each noticed the actions of the other. In the end, it turned out that both accomplices drank poisoned water. “Battled, they collapsed on each other, finding comfort in death. The lips of the young woman touched her husband's neck - the place where Camille's teeth scar remained. The corpses lay all night on the dining room floor, at the feet of Mrs. Raken, twisted, ugly, illuminated by the yellowish reflections of the lamp. For almost twelve hours, until noon, Mrs. Raken, motionless and dumb, looked at them, destroying them with her heavy gaze, and could not get enough of this sight. ”