In this sequel to Brat (The Brother), this film opens with Danila Bagrov (Sergei Bodrov Jr.) being interviewed on television with two friends from the army. All three now live in Moscow, where Ilya Setevoy (Kirill Pirogov) is a programmer at a history museum, Konstantin (Kostya) Gromov (Alexander Dyachenko) works in security for a bank.
After the interview, the friends retire to a bathhouse where Kostya reveals that his twin brother, Dmitry Gromov, is an ice hockey player for the Chicago Blackhawks and is being blackmailed by American kingpin Richard Mennis (Gary Houston). According to Konstantin, Dmitry once played for his home club he was invited by the NHL and emigrated to the United States. After he moved, the Ukrainian mafia moved in on him, demanding protection money. Dmitry (also portrayed by Alexander Dyachenko in a dual role) was desperate and appealed to Mennis for protection. Mennis took him under contract, but it left Dmitry as an indentured servant as all proceeds are paid to Mennis. Konstantin informs that Mennis has come to Moscow to meet his employer, Valentin Belkin (Sergey Makovetsky) to discuss a business proposal.
In Priozersk, Danila's brother Viktor (Viktor Sukhorukov) watches the interview with their mother. Seeing how her older son has turned into a drunken policeman, she pleads that Viktor travels to Moscow and seek his brother there. After the bathhouse, Danila meets up and begins an affair with pop singer Irina Saltykova (playing herself), who he met at the TV station.
The next morning, Kostya approaches Belkin and pleads to remind Mennis about his brother. Belkin agrees, but Dmitry Gromov is of little concern to both of them. Belkin, being a Russian kingpin himself, wishes to cooperate with Mennis to legalize their assets. That evening, Danila stops at Kostya's apartment to discover him shot dead.
After being briefly arrested and getting into a fight in jail, Danila and Ilya begin planning their revenge in the museum. On the black market, they purchase a CD with personal information about Belkin. They also purchase guns from a neo-Nazi friend of Ilya's. Meanwhile, Viktor has arrived in Moscow and manages to find find Danila in the museum, where he agrees to join their plans, and helps them steal a car.
As it is the start of the school year of September 1, the gymnasium where Belkin's son Fedya is studying is holding its opening ceremonies. Arriving at the school in the stolen car, Danila introduces himself as Fedya's new teacher and invites Belkin to the staff-room for a private conversation. He confronts Belkin at gunpoint and interrogates him about Kostya's murder. Belkin reveals that it was not his doing, but that of Mennis. Danila leaves Belkin after he pleads for his life.
The trio clear the museum, and Danila gives Ilya his remaining money to procure passports and tickets to Chicago. It is revealed that Kostya's murder was due to a misunderstanding, as he only wanted him fired. However, the stunt in the school now threatens his whole operation with Mennis. Belkin's thugs and his police contacts begin to search the city for Danila. Danila decides to lay low at Saltykova's apartment and brings Viktor with him. Meanwhile, Belkin's thugs discover the stolen car in the building's parking lot. Saltykova's chauffeur Boris warns Danila, and the Bagrov brothers ambush the mobsters and then lead them on a chase through the town and into a closed alley, where they make quick work of the thugs. News of Bagrov's success concern Belkin's partners, who begin doubting the security of their operation. Learning of the bought tickets under Bagrov's name, Belkin alerts the Ukrainian mafia in Chicago.
To avoid capture, the brothers fly to America separately, and Viktor arrives in Chicago without any suspicion. Danila instead takes a flight to New York City where he arrives in Brighton Beach. There, he buys a cheap car to travel to Chicago by road, but it breaks down along the Pennsylvania Turnpike. Stranded, he hitches a ride to Chicago with trucker Ben Johnson (Ray Toler). Despite Danila's limited English, the two become close friends and on his way to Chicago, Ben shows Danila much about American life. Upon their arrival in Chicago, Ben drives by prostitutes, one of whom, Marylin, turns out to be a Russian named Dasha (Darya Urgens Lesnikova).
Back in Moscow, Belkin is still determined to catch Danila, but a background check revealed that Viktor was on board the flight to Chicago. Paranoid, Belkin alerts the Ukrainian mafia in Chicago to find him. Meanwhile, Viktor arrives to the Ukrainian district in Chicago. Danila attempts to meet up with Dmitry and Viktor, but is unable to make contact with them. Badly needing a translator, he decides to find Dasha and travels to the neighborhood where she works. Just before he can run away with her, he is savagely beaten by Dasha's pimp's henchmen. The Police let him go on the basis of recognizance and he gets revenge by tricking the same group into selling him weapons, which he steals by subterfuge. Afterwards, Dasha's pimp attempts to get even with her but is in turn killed by Danila, leaving Dasha no choice but to go with him.
Danila and Dasha finally meet up with Viktor and the three enjoy an evening campfire on the beach of Lake Michigan where they share their experiences and attitude towards American society. Dasha tells her story of how she came in the early 1990s as an exchange student, worked in escort service in New York before finally degrading into a street hooker. Viktor, on the other hand, is much too impressed with the power of money that drives America. Danila instead shows his patriotism and offers Dasha to come back home with them, replying to her "what will I do there?" with the "What have you achieved here?" inferring to her social status. As for Viktor, Danila reminds him there are things that money can't buy. This philosophical discussion is broken by a homeless black man, who stumbles across them and is insulted when Danila called him a negr (not knowing that the word is an insult in English). While waiting for a fight to come, Dasha replies that she believes that the aggressive primal nature of black people drives fear into white people, thus making them ultimately superior. This theory fails its test, when Danila's warning shots into the sand quickly forces the attackers to flee.
Regardless, Danila finally begins to move in against Mennis and first hits his front, the Club Metro. Expecting Mennis to be there he sneaks a weapon into the toilet, and during a Rock concert that evening, involving the Bi-2 band, he kills every member of Mennis' mafia he encounters in the basement. Mennis, alas, is absent. Viktor, himself picked up a tail by the Ukrainian mafia, draws them away and kills their hit-man, but not before learning of the mafia's operations and headquarters. The next morning Danila climbs 50 or so floors on a skyscraper's fire escape to reach Mennis' office. He finds him in a game of chess. Killing his colleague, he finally confronts him alone. As if continuing the debate on the lakeside, in his monologue (in Russian) he asks the American if power really comes from money. Arguing that his brother (whose photo is lying next to the chess table) believes this theory, Danila instead thinks that power lies in the Truth. He (implying Mennis), can be rich, but not strong, as his money he stole from someone else. Thus the tricked person is right, so he is stronger. Almost weeping in fear, Mennis agrees. In conclusion, he demands all of the money he took from Dmitry to be returned.
Giving Dmitry his money, Danila sets off back home to Moscow driving through the Ukrainian neighborhood he witnesses a police siege around the former headquarters of the Ukrainian mafia, where Viktor killed everyone inside. As he is dragged out handcuffed, Viktor shouts his intentions to stay in America. The film ends with Danila and Dasha taking off to Moscow, and the final call to Irina is not intercepted, as presumably, Belkin is also removed by his "investors", who in an earlier scene, face to face told him, that the sum of money he set up in this operation is too much to be risked. At the airport, Dasha is told that she will never be able to enter the United States again due to the expiry of her visa, but she does not care, signaling an intention she will never come back.