An attempt was made on businessman Marat Shaikenov. Shaikenov believes that this is the same sniper who has been keeping the entire city in fear for a month, committing more and more murders. Shaikenov turns to the Beagle detective agency with a request to find the sniper. Moreover, death now threatens not only him, but also his fiancée Ella. Investigating this complicated case, private detective Andrei Rostovtsev meets family psychologist Alina Belova, who, thanks to her professional experience, helps Rostovtsev identify the criminal. Rostovtsev invites Alina to become a member of his team.

Alina's fiancé, the famous journalist Dmitry Aristov, lost a flash drive with compromising information on Deputy Governor Stanislav Kravchenko, who, according to his wife Maryana, was involved in the murder of their housekeeper. The detectives, along with a new member of the team, 18-year-old Young, get down to business. One version replaces another, mysteries multiply. Thanks to Alina's professional instincts, she manages to figure out the true killer, whose name comes as a surprise to the whole team. After the successful completion of the case, Alina accepts Andrei Rostovtsev’s offer to become a full-time psychologist at the Beagle detective agency.

A certain Konstantin Rykov comes to the BEAGLE agency. He suspects that his wife Sonya is not faithful to him. In a conversation with Alina, Sonya admits that she really has a secret that she is afraid to share with her husband. It turns out that Sonya was raped by a serial maniac nicknamed “Elevator”, who is not the first time to attack women. To identify the criminal, Alina decides to take a risky step: she is ready to become “bait” for the maniac. With the help of Petrovich and Yoongi, she manages to catch the rapist. However, new details unexpectedly emerge: Alina suspects that Sonya is lying: “The Lifter” had nothing to do with her rape.

Businessman Stepan Kireev approaches Andrei Rostovtsev and asks him to find Judge Zobov as soon as possible. Zobov received a large bribe from Kireev for promising to make a judgment in favor of the businessman, and then disappeared. During the investigation, unexpected details from the life of the judge begin to emerge. It turns out that Zobov had pathological honesty, which is confirmed by the agency secretary Vera Antonovna, who worked with him many years ago. In addition, it turns out that the 60-year-old judge had a young mistress. But most importantly, the detectives learn that Judge Zobov is terminally ill. So what made Zobov commit malfeasance? And where is the judge now? Private detective Andrei Rostovtsev and his team are struggling with these mysteries.

His son Stepan was found murdered in the house of pensioner Efimov. The matter is complicated by the fact that all suspicions fall on Beagle Agency employee Dusan Petrovich. Petrovich violated the orders of his boss and went to the pensioner’s house to help Stepan find an ancient treasure hidden in the house. Prosecutor's office investigator Borodulin promises Rostovtsev to put Petrovich behind bars. The whole team does not believe that Petrovich is guilty and is trying to help their friend. Together with Yunga and Alina, Andrei Rostovtsev manages to solve this crime, which has roots in the distant past.

Pensioner Vasilisa Yegoryevna contacts the agency with a request for help: she believes that her grandson is unfairly serving his sentence for the murder of his neighbor. After all, in fact, the neighbor is alive. At the same time, Danish citizen Lars Lange was killed in his hotel room. Investigator Borodulin suspects that the foreigner was a client of the Beagle agency. At first, these unrelated events gradually acquire common features. The trail leads detectives to a young woman, Stasya, who, for the sake of her child, decides to kill her close friend.

His ex-fiancee Anna comes to Nikita with a request to find her missing husband Maxim, with whom Nikita was once friends. Soon the police discover Maxim's body. At first, random hooligans with whom Maxim, nicknamed Elephant, allegedly got into a fight, come under suspicion, then criminal businessman Cheng, who dreams of extorting his debt from Elephant. And only after Beagle manages to bring up the materials of an old case: Nikita’s motorcycle accident, as a result of which he became disabled, Rostovtsev begins to realize that the same person is behind these two crimes.

Alina and Beagle are quarreling. Alina accuses Rostovtsev of neglecting ethical standards when working with clients, and in general he doesn’t care about people. Therefore, when a new client, cemetery watchman Ivan Nikolaevich, comes to the agency and reports that he discovered an ownerless corpse in the cemetery at night, Beagle immediately entrusts Alina with independently investigating this seemingly trivial matter. The next day, Alina receives a message that Ivan Nikolaevich died: being drunk, he burned down in his lodge. The habit of not believing in accidents forces Alina to continue the investigation. Understanding the seemingly insignificant circumstances of the case, Alina does not suspect that she will be faced with the criminal secrets of the funeral business.

The parents of seventeen-year-old Lera Vaseliadi contact the Beagle agency with a request to find their daughter. She left home three days ago, but never returned. Soon the detectives discover two corpses. An unknown killer dealt fatal blows to Lera and her grandmother with an ax. Beagle promises the mother of the dead girl to do everything possible so that the villain is found. At first, suspicion falls on a graduate student of the Faculty of Philology of Moscow State University, a Dostoevsky lover, Kirill Dvorak. However, Alina, who returned from vacation, seriously questions this version.

Svetlana Vetvinskaya’s only 23-year-old daughter Masha committed suicide. The inconsolable mother asks Beagle to find out the reason why Masha did this. Having studied her past, Alina makes the assumption that the girl, apparently, did not need any special reason to commit suicide. Apparently, Masha was very lonely. However, after an investigation, detectives put forward an unexpected version - it is a murder. It turns out that Masha turned out to be a victim of her own cruel plan: to take revenge on her mother for her warped childhood.

Museum worker Varvara Popova lost her 22-year-old son Misha. She wants the Beagle Agency to keep him under surveillance. It soon turns out that Misha simply fell in love. The object of his passion was a certain Olga Burlakova, 28 years old, the widow of the famous antique dealer Viktor Burlakov, who was killed in his apartment a month and a half ago. Varvara Dmitrievna demands that Rostovtsev find incriminating evidence on Olga. She is sure that this woman, whom her son contacted, is involved in the murder of her husband. Varvara Dmitrievna does not yet know what shocking truth about her son she will have to hear.

Marina Makarova contacts the Beagle agency with a request to find her husband Valery, who is running away from a divorce. Marina does not hide the fact that she is leaving her husband after twenty years of marriage for a young lover with whom she is going to build a new family. At first, the detectives put forward the version that Valery, being in a depressed state, went somewhere. However, after an investigation, they discover Makarov’s corpse buried in the forest. Andrei Rostovtsev, together with his team, are struggling with the question: why could they kill a modest security guard?