At an orphanage, 10-year-old Amudha is told by the caretakers that someone important is going to meet her in the next day at 10:00 am; She waits anxiously, wondering who it may be. Meanwhile, a smuggling van carrying a ton of cocaine from an interstate group of smugglers are seized by Inspector Bejoy and his team. The contraband was smuggled by a huge gang headed by Adaikalam, the most wanted smuggler in Tamil Nadu, whose identity remains unknown. Adaikalam's brother Anbu plans to capture the five police officials, kill them, and retrieve the contraband. According to Anbu's plan, all the police officials in the city get unconscious after consuming poisoned drinks at a higher official's retirement party. Bejoy, who avoided the drink as he was under medication, tries to save the lives of all the unconscious officials without letting the media or anyone else finding out.

Bejoy convinces Dilli, an ex-prisoner who happened to be there with him as he was detained for looking suspicious (and being the only one who can drive a lorry), to help him save the officers' lives by threatening him that he would not let him meet his daughter Amudha the next morning, with the help of a lorry borrowed from Kamatchi, a caterer present at the party. As Kamatchi has navigations of routes and roads, Dilli tells him to come with them as well. Dilli, Bejoy, and Kamatchi together load the unconscious officials into the lorry and try their best to get them to the hospital as soon as possible without any casualties. As Anbu announces a huge sum of money as the reward for catching the policemen, gangsters from Anbu's gangs try to hunt down Bejoy and his team. They are guided by Paalpandi, a corrupt cop (recruited by Stephen Raj, Zonal Head of Narcotics Division) who pretends to be unconscious while giving information about the location of the lorry to the gangs.

Meanwhile, at the commissioner's office, the drugs are hidden along with Adaikalam's men who are in custody. As Anbu and his gang would take the drugs and free Adaikalam's men, Bejoy orders constable Napoleon and a group of college students detained due to drunk driving, to close all the possible exits and to try and keep the gangsters outside the commissioner's office at the cost of their own lives while they wait for higher officials. Dilli, Bejoy, and Kamatchi come across the various gangs, but Dilli takes care of them brutally. Back at the building, Napoleon is instructed by Bejoy to negotiate a deal with the captured men of Adaikalam. Napoleon makes one of the men call Anbu and agrees to release the prisoners in exchange for his and the student's safety. Surprisingly, Anbu agrees. However, Bejoy realises that Adaikalam himself is captured unknowingly with his men and instructs Napoleon to cancel the deal.

Adaikalam tries to guide Anbu into the commissioner's office, but the students purposely blast loud music to keep him from hearing Adaikalam. Anbu manages to climb up to the roof and break into the building, but he is subdued by the students and tied up. Dilli and Kamatchi manage to transfer the unconscious officers to a school bus from the hospital so that they can continue to the commissioner's office. However, they come across another huge and armed gang under leadership of Tips who were ordered by Anbu himself to kill both Dilli and Bejoy. They beat up Bejoy, and Paalpandi brutally stabs Dilli but Dilli manages to kill Paalpandi and all the gangsters including Tips, while rescuing Bejoy and proceeding to the building. Anbu's gang is outside the building and Ram manages to catch a student, and under the order of Anbu, kills him. Infuriated, Napoleon bludgeons and renders Anbu unconscious with a fire extinguisher, to which Adaikalam swears he will kill all of them.

Dilli, Bejoy, and Kamatchi make it to the building. Dilli alone enters the building through a secret passage and sends the students through the passage, while he and Napoleon go to burn up the cocaine. The duo reaches the storage room, but to their surprise, they also find a confiscated M134 Minigun. Instead of just burning the drugs, Napoleon decides to eliminate all the syndicate members. They reach the ground floor as the goons break-in. Dilli uses the gun to kill Ram and all of Anbu's gang outside the building. All the policemen are resuscitated, and Bejoy finds the moles in his department. Stephen Raj is incriminated and all injured are moved to the Government Hospital overnight. Bejoy thanks Dilli and promises him that he will soon arrange a good life for him and his daughter. Nalini, who is Dilli's probation officer, brings Amudha to the spot, and they meet with tears of joy.

In prison, one of the captured men tells Adaikalam that Dilli, who had no connection with the gangs, was the prime reason for all of their losses, to which Adaikalam, who already knows Dilli, replies that he does have a connection. The next day, Dilli, Amudha, and Kamatchi leave for Dilli's village.