Maharashtra Police seizes a large quantity of arms from a house in the communal riot torn town of Chandangarh. The house belongs to Dr. Iqbal Ansari (Atul Kulkarni), a Muslim doctor. The police conclude that he is an agent for ISI, and is responsible for engineering the riots. Ansari is arrested and is set to be presented before a special court in Mumbai. However, the convoy of police vehicles transporting Ansari from Chandangarh is ambushed by an unknown group. The police team manages to secure him, but suffers heavy casualties.

Additional Commissioner of Police, AD.CP Naidu (Prakash Raj) assemble a team of five police officers to bring Ansari to Mumbai so that he may appear in the special court for the hearing. The leader of the team, DCP Anant Shrivastav (Amitabh Bachchan), is an honest policeman at the end of a failed career, because he refused to bend for the corrupting forces in the system. He accepts the mission, thinking that his career will finally mean something and he will be promoted to Additional Commissioner of Police in recognition of his efforts and his service. His team consists of Senior Inspector Shekhar Verma (Akshay Kumar), a corrupt cop, rookie Sub-Inspector Ashwin Gupte (Tusshar Kapoor) and two constables, Kamlesh Sawant and Gajanan Mhatre.

Before their departure, the team catches a photographer who is trying to take pictures of them. He is revealed to be linked to Yashwant Aangre (Ajay Devgn), who is spying on the team. Aangre kills the photographer and his entire family by linking explosives to their telephone's receiver in order to destroy any links the police might discover between himself and the photographer.

When the team reaches Chandangarh, the police receives a call from a school teacher named Mahalakshmi (Aishwarya Rai), who suspects that the people living on school's property are terrorists. The team accompanies the local police to find a corpse in the terrorists' room. When they raid the room, the phone rings, but Anant ensures that no one answers it, and discovers a bomb linked to the phone, set to go off when anyone answered it. He also finds evidence that the group staying there had information about their travel plans, which prompts him to change them.

Back at the police station, Ansari's mother (Tanuja) and son come to see Anant, and plead with him to ensure that Ansari reaches the court, instead of killing him en route. Shocked to hear this, Anant promises her that she will see her son in court. Anant then receives a call from Aangre, who appears to know him. Anant is unable to recognise him, and all attempts to trace the call fail. He hears the voices of his wife and daughter on the line, but it turns out that it is a recording that Aangre played to scare him.

The team, along with Mahalakshmi, leaves for Mumbai by road, only to find the highway blocked by a pile-up. They decide to take a dirt track to bypass the pile-up, but find their way blocked by an extremely crowded cattle fair. While trying to clear a path for the convoy, Anant gets a call from Aangre, who is present at the scene in disguise. Anant spots him and chases him through the fair along with Ashwin Gupte. Shekhar Verma, realising that the place was perfect for an ambush, ensures that no one gets near the van carrying Ansari.

Aangre causes a stampede, and Anant fails to catch him. As the team carries on, Shekhar realises that he left the Jeep unguarded while he was trying to guard the van. He pulls over and sees a bomb attached to the bottom of the Jeep. He makes sure that everyone gets away from it in time, but the Jeep explodes, and the shock wave of the blast causes damage to the van's engine.

The team pushes the van to a secluded house off the highway, where they decide to stay until they repair the van. Anant calls Naidu to appraise him of the events, and tells him their location so that he can send a police team. At the house, as Anant is trying to figure out who the man at the fair was, he remembers Aangre, an extremely corrupt and ruthless ex-cop, who was thrown off the force and imprisoned after Anant caught him killing five innocent men.

The team sees a police van outside, and think that it is the rescue team, but it turns out to be Aangre's men. After a few minutes of heavy firing, which thoroughly depletes the team's ammunition, Aangre's men drop off the body of the constable who was trying to repair the police van, along with a message to hand Ansari over to them. Shekhar, realising that there is no alternative, grabs Ansari and tries to hand him over, but Anant stands in his way. There is a showdown between the two, in which Shekhar accuses Anant of being a useless cop who's going to get them all killed because of his high-minded principles.

The argument reaches a point where Anant and Ashwin have their guns trained on Shekhar. At this point, Ansari breaks down and tells them that the terrorists are there to kill him, not free him. He goes on to reveal that he was an honest citizen living in Chandangarh with his family when a journalist, Bhaskar Joshi, came to him and revealed that the communal riots were actually engineered by minister Deodhar, who killed off a few social workers who had compiled evidence that would've put him in prison for a long time. Bhaskar was in possession of the file containing the evidence, and wanted Ansari to give him the post-mortem reports of the social workers so that he could expose Deodhar. However, Bhaskar was killed before he could do that, and Ansari began to receive threatening calls asking him to hand over the file of evidence against Deodhar. When he refused to cooperate, corrupt cops destroyed his house, killing most of his family, and framed him as a terrorist.

Meanwhile, Aangre and his men enter the house and hold everyone at gunpoint, except Shekhar and Ashwin, who manage to sneak Ansari to the warehouse attached to the house. As his men try to find them, Aangre tells Anant that his idea of revenge is to take away what matters the most to Anant - honour and dignity - because they mean much more to him than his life. Aangre's men locate the warehouse, but when they enter, they see a few LPG cylinders, which Ashwin shoots at from outside, causing an explosion that kills some of Aangre's men. The team manages to get into the police van, but as they're driving away, Aangre manages to shoot Ansari, who gets gravely injured. Anant then receives a call from Naidu, who accidentally lets slip that he knows that Ansari has been shot. Anant realises that Naidu is actually a corrupt cop working for Deodhar, and he was responsible for giving Aangre information about their travel plans at every turn.

The team takes Ansari to a hospital in a small town, where the doctors manage to save him, but declare that his condition is quite serious. Anant tells his team that they're free to leave, since the very people who sent them on the mission do not want them to succeed. He tells them that he has decided to go on right till the end. Shekhar apologises for their showdown the night before, and says that he would accompany Anant right till the end, if only to make up for being a corrupt cop. The rest of the team also decides to go with him.

The local police find out about the team and bring them over to police station, telling them that they have orders to relieve them and take charge of Ansari. Anant gives the officer in charge a fiery speech about how unbelievably corrupt the police force is, and how politicians like Deodhar can get away with anything only because cops like Naidu do their bidding. The officer decides to help them, and tells Naidu on the phone that they've arrested the wrong people.

At this point, Deodhar and Naidu come up with a plan to turn the local public against the police team by declaring in a press conference that the team has gone rogue and is now answering to ISI. Seeing the news on television, several locals gather at the hospital and threaten to kill Ansari. Anant confronts them head on, and tells them that they do not know what the truth is, and are being used by corrupt politicians for their personal gain.

They manage to get away to a railway station, where they're supposed to catch a service train to take them to Mumbai. Aangre and his men arrive on the train, but the team has taken precautions. Constable Kamlesh drives away from the station in the police van as a decoy. Aangre and his men fire at the van, thinking that the team is in it, but Shekhar manages to take control of the train, and the team boards it while engaged in a shootout with the terrorists. Kamlesh stops the van close to the tracks and tries to catch the train, but fails and is shot dead by Aangre.

Upon reaching Mumbai, when Ansari is being carried into the hospital, the doctors realise that he has succumbed to his injuries and died. His mother, thinking that Anant did exactly what she begged him not to do, slaps him in front of a host of reporters before he can explain things to her. The team however, gives Ansari a proper burial, and declare to the media that the case is not over.

Enraged by Anant's statement to the media, Deodhar invites him over and tells him to toe the line, but Anant refuses to bend. Later, the team tracks down journalist Bhaskar's son, who has unknowingly had the location of the file is all along. Shekhar and Mahalakshmi go to the grand post office and recover the file, but Aangre ambushes them. After a fight, Shekhar hands the file to Mahalakshmi and tells her to take it to Anant, while he stays back to fight Aangre's men. However, he is lured into a stadium where it is revealed that Mahalakshmi is actually Aangre's girlfriend and was planted on the team by him to find out where the file is. Aangre's men brutally shoot down Shekhar, but not before he places a call to Anant, letting him know that Mahalakshmi was a double agent.

Anant and Ashwin manage to track Aangre down by following Mahalakshmi. In a shootout, Aangre uses Mahalakshmi as a shield and she dies. Anant chases Aangre and manages to surround him with a large number of cops. Enraged by the horrors Aangre has inflicted throughout, Anant beats him unconscious before he is held back by the police force.

Armed with compelling evidence from the file, the court is able to convict Aangre, Deodhar, and Naidu. On the way to prison in a police van, Aangre sees that the bolts holding his handcuffs are actually loose. Breaking free, he grabs a rifle and attacks the constable in the van. Ashwin jumps out of the van to find Aangre pointing a rifle at him. Aangre pulls the trigger, but there are no bullets in the gun. He puts the gun down and surrenders with a smirk, but Ashwin shoots Aangre twice, and shows him the screws of the bolts, indicating that they were deliberately removed. Ashwin instructs the constable to stage the scene and then calls a senior officer to say that Aangre has been fatally wounded while trying to escape from custody.

• Amitabh Bachchan as DCP Anant Kumar Shrivastav
• Akshay Kumar as Senior Inspector Shekhar Verma
• Ajay Devgn as Yashwant Aangre
• Aishwarya Rai as Mahalakshmi
• Tusshar Kapoor as Sub-Inspector Ashwin Gupte
• Kamlesh Sawant as Constable Kamlesh Sawant
• Sabyasachi Chakrabarty as Minister Deodhar
• Prakash Raj as Additional Commissioner of Police Shrikant Naidu, Angre's main mole in the police force
• D. Santosh as Constable Gajanan Mahatre
• Prasanna Ketkar as Constable Ghorpade from Chandangarh
• Yusuf Hussain as Police Commissioner
• Atul Kulkarni as Dr. Iqbal Ansari
• Tanuja as Dr. Iqbal Ansari's mother
• Jaya Prada as Jaya Srivastav
• Vivek Vaswani as smuggler
• Ashwini Kalsekar as Kamlesh's wife as special appearance
• Abir Goswami as Photographer as friendly appearance
• Lara Dutta as Herself, in a cameo appearance

The film's co-writer Sridhar Raghavan, knew Santoshi, who wanted to make a cop film with Amitabh Bachchan, through Anjum Rajabali. During their meet, Raghavan narrated a script to Santoshi about cops which he liked. Raghavan said: "We kept that as a base and started working afresh, collaborating, writing, rewriting." They created a character for Bachchan, inspired by Zanjeer in the "21st century situation".

The film was shot in various parts of Maharashtra, including Mumbai and Nashik. The fictional city of "Nairoli" shown in the film is actually the city of Apta near Panvel. The railway station of Apta was rechristened as Nairoli for the scene featuring the shoot-out at the station. Ram Sampath composed the music for the film, with lyrics by Sameer.

Akshaye Khanna was originally supposed to play the role which Tusshar Kapoor played. Ajay Devgn was initially offered Akshay’s part but he turned it down. He did the role of Yashwant Angre instead, making it his second role as a villain.

While filming in Nashik, Aishwarya Rai was hit by an out-of-control jeep and was thrown back into some bushes by the side of the road. She and Tusshar Kapoor were rehearsing a scene where the jeep was supposed to come and stop 20 feet away from them. However, the jeep driver lost control and did not brake. She suffered a fracture on her left foot and some bruises.

Since its release, Khakee<