In the lobby of the fashionable London hotel "Bertram" - the embodiment of old England - the guests gather for an evening tea party. The elderly ladies present pay attention to Bess Sedgwick, one of the most notorious women in England. Bess was an active participant in the French Resistance, a brave pilot, a race car driver. At sixteen, she fled from the house with the groom, but her parents hushed up the scandal, marrying her to a rich old man. Soon Bess left him and subsequently often changed husbands. Now she is a rich woman living on alimony.
One of the hotel guests, Miss Marple, pays attention to Bess. The old lady seems strange that the extravagant Bess chose such a respectable hotel.
The hotel includes a girl. Supervisory Miss Marple notices that upon seeing her, Bess changes her face. A girl named Elvira meets in the hotel lobby with her guardian, Colonel Laskom. She was brought up in a boarding school, now she wants to enroll in secretary courses, and for now she will live with her relatives. The colonel tells his pupil that when she turns 21, she will be able to manage her condition.
Elvira draws attention to the young and famous driver Ladislav Malinovsky, who entered the hall. He leaves the administrator a note for Bess.
The hotel is distracted by the canon Penifaser, who is traveling to a conference in Switzerland. He will not be in London for several days, but he reserves the room.
Bess meets with Colonel Laskom. Elvira is her daughter, but she prefers to stay away from her. Bess loves to endanger herself, why does a child need such a mother?
Bess and hotel doorman Michael Gorbman are old acquaintances. The hunchback reminds Bess of one circumstance from her life. Bess warns him to be silent, otherwise she will kill him. Once he was well paid for silence.
Elvira needs to leave for a day in Ireland, and she asks her friend Bridget for help to deceive her guardians. To get money for the trip, Elvira and Bridget go to a jewelry store, where Elvira has been known since childhood. While Bridget is distracting the seller, Elvira steals the bracelet that Bridget must put into the pawnshop.
Taking a walk in the morning, Miss Marple enters one of the city's restaurants for lunch. There she meets Bess with Malinovsky. The old lady manages to eavesdrop on their conversation. They talk about the plane to Switzerland, and Bess is unhappy that Ladislav came to the hotel yesterday.
Canon Penifazer arrives at the airport, where it turns out that the flight to Switzerland was yesterday. The frustrated canon returns to his hotel room, where he is hit hard on the head.
Not far from London, the Irish Express is robbed.
Elvira returns from Ireland. She found out what she wanted, but the news did not please her. With an innocent look, she returns the stolen bracelet.
The girl turns to the law office for help. Her father died when she was five years old, her mother escaped from him, and Elvira never saw her. The girl is interested in when she can manage her condition. After adulthood or marriage, she will receive a large sum. From a conversation with Elvira, the lawyer realizes that she has a friend, and reports this to the colonel, advising her to follow the pupil.
The canon’s housekeeper, worried that he hasn’t arrived yet, is calling the Bertram Hotel, but the canon is not there. A friend of the canon, after unsuccessful searches, decides to contact the police.
Miss Marple, walking around the city, enters the cafe for lunch. There she sees Elvira along with Malinovsky.Carefully examining the girl, the elderly lady notices the similarities between her and Bess - no doubt they are mother and daughter.
At the Bertram Hotel, due to the disappearance of the canon, police appear. Having found out nothing from the staff, they decide to speak with Miss Marple, who knows Penyphaser well. Miss Marple confirms that the canon left the hotel in the evening, but at night she looked out into the corridor and saw him leaving his room in a coat. The maid shows that no one spent the night in the room.
The penyazer comes to life in an unfamiliar house, in some village. The owners of the house found him on the road, where the canon hit a car.
Investigating the case of a train robbery, the police are interested in Ladislav Malinovsky. The young man has a bad reputation for women, dubious sources of income and the same car as they saw near the place where the train was robbed. Bess has a car of the same brand. Due to the mysterious disappearance of the canon, the police are interested in the Bertram Hotel. Miss Marple saw the priest at the hotel, and another elderly lady claims to have seen him in a robbed train.
The police finds a canon who can hardly remember what happened to him.
After checking the identity of the owner of the hotel, the police determine that the owners are two Swiss brothers, one of whom is in banking circles, and the second is holding a jewelry store, both own real estate, and both are seen in questionable transactions. The police believe that the brothers finance many crimes, but who organizes these crimes?
Police Inspector Meets Miss Marple. An elderly lady believes that Elvira is in danger when meeting with Malinowski. The inspector tells her about the canon.
Miss Marple and the inspector are interrupted by gunfire and female screaming. On the street, in dense fog, they see a frightened Elvira leaning against a garden fence and the dead doorman Michael Gorbman lying at her feet. The girl tells the inspector that she was walking along the fence when shots rang out. The doorman covered her with himself, and she could not see the shooter in the fog. She reports that this is the second attempt on her life: once in a guesthouse she was poisoned by sweets thrown into her room, and upon arrival in England she received a threatening letter. Bess, who does not now depart from her daughter, believes that this is nonsense. Elvira denies meeting Malinovsky, but the inspector does not believe her.
The inspector talks to Bess. She believes that her daughter does not know Malinovsky, and considers the assassination attempts on Elvira a complete stupidity.
The inspector talks to Bridget. The girl confirms the story of poisoned sweets and the acquaintance of Elvira with Malinovsky. She talks about a friend’s trip to Ireland.
The inspector visits Elvira’s lawyer and meets with Malinovsky. He confirms that he has a gun that holds in the car, but he is not there. The rider is surprised to learn that Horbman was shot from his pistol. He denies the charge of attempted assassination of Elvira - why should he kill the girl he is going to marry, although he is her mother’s lover?
The inspector goes to Ireland. Returning, he meets with Miss Marple. Canon Penifaser comes to the hotel. The inspector is trying to restore the events of that night when the canon disappeared. Miss Marple understands that it was not the canon she saw at night. The priest recalls that when he entered the room, he saw his double there.
Inspector and Miss Marple are dating Bess. The inspector knows her secret: Michael Gorbman was Bess's husband. He worked as the groom for her father, and they fled, secretly married. Subsequently, Bess got married, already being a married woman. When Bess spoke with Humpman, she did not know that Miss Marple and Elvira had heard her conversation. The girl went to Ireland to find out the truth. The inspector assumes that the doorman was killed by Malinovsky.Michael knew the hotel was the headquarters of a major crime syndicate. Many hotel employees are involved in scams abroad. One of them, having disguised himself as Canon Penifaser, robbed a train, but because of the distraction of the canon of criminals, they failed, they were exposed. Heads the criminal community of Bess.
Bess confesses everything. She emphasizes and calls in witnesses to Miss Marple that she killed the doorman, not Malinovsky. Then Bess tries to escape - breaks the window, running through the ledge, gets into his car, crashes into the fence of the park and dies.
Miss Marple and the Inspector are clear that she is not a killer. The inspector does not understand who killed, but Miss Marple is sure that it is Elvira. Upon learning that her parents' marriage was illegal, the girl was afraid to lose her fortune, although her father left the money to her. Having stolen a gun from Malinovsky, Elvira shot into the air, and when the doorman rushed to her, shot him in cold blood, hoping that a thick fog would hide the imaginary killer. But how to prove it?
Elvira calmly accepts the news that her mother is a murderer. The inspector swears that he won’t leave it like that, and Miss Marple calls on the gentlemen to have mercy on the girl’s soul.
