Billa

During a police chase, David Billa is severely wounded in an accident and dies in front of DSP Jayaprakash. Jayaprakash secretly buries Billa and keeps his death off the record, allowing the pursuit to continue under the assumption that Billa is still active in the shadows.

Interpol officer Gokulnath and Jayaprakash decide to target Billa's network. They locate Saravana Velu, a hotel server and petty gangster who resembles Billa, and recruit him to infiltrate the gang by posing as Billa. Jayaprakash promises Velu that his adopted son Karan will receive a proper education in return.

Jayaprakash trains Velu and sends him back to Billa's gang disguised as an amnesiac Billa living in an apartment complex due to injuries. Velu begins to learn the gang's structure and even speaks to Jagdish, Billa's boss, on the phone to gather intelligence.

Velu provides a pen drive containing the network's secrets to Jayaprakash. Sasha, seeking revenge for her brother Rajesh and his fiancée Rhea's deaths at Billa's hands, tries to kill Velu. Jayaprakash arrives and reveals to Sasha that he is Velu and not Billa.

Velu secretly informs Jayaprakash about the meeting of Billa's network before a party. C.J., Billa's girlfriend, overhears Velu's information and confronts him; in the ensuing struggle, Velu accidentally kills her.

A shootout erupts at the party, and Jayaprakash is killed by Jagadish, who leaves behind his gun. Velu finds Jayaprakash dead and the gun, but he is captured by a police team led by Gokulnath.

In police custody, Velu argues that he is Velu and not Billa to Gokulnath. Velu mentions the pen drive as key evidence, but the pen drive is nowhere to be found.

Unable to prove his innocence, Velu escapes from a police van and phones Gokulnath. At the Aero Bridge, it is revealed that Gokulnath is actually Jagadish, the man who killed Jayaprakash.

Officer Anil Menon has kept the pen drive all along and strikes a deal with Velu to help bring Jagdish to justice. The pen drive becomes a bargaining chip in the struggle against Jagdish.

Jagadish kidnaps Sasha and Karan and demands the pen drive in return for their safety. Velu responds to the escalating danger as the stakes rise for everyone involved.

Velu meets Ranjith and hands him a second pen drive containing the same data, but the drive is corrupted. This move tightens the pressure on both sides as trust frays.

Ranjith attempts to kill Velu; a scuffle ensues and Ranjith falls from the top, ending his threat. The incident further destabilizes Jagdish's circle.

Jagdish, posing as Gokulnath, engineers an arrest of Velu as Billa, but the police uncover the ruse after they wire Jagdish and Velu's conversations. Jagdish is shot by the police and dies, exposing Velu's innocence.

Velu hands over the original pen drive to Officer Menon and joins Sasha and Karan, choosing to protect his adopted family over the gang. The ending shows him stepping away from Billa's shadow and toward a hopeful future.