Raghu, a normal college guy gets dragged into trouble when he falls in love with Lekha and their whirlwind romance changes the course of his life.

Raghu lives with his family in Pollachi, and has an elder brother named Thiru, who left their house after his girlfriend was killed during a biking trip. Raghu is in his final year of college studying Computer Science and Engineering when he meets an actress Lekha, who is forced to act against her will. After a few more encounters, they become friends which eventually blossoms into love. Raghu takes her to his house to introduce Lekha to his parents and they accept her. However, a film director named Kuberan and producer arrives at Raghu's house and takes Lekha away after threatening Raghu's family. Raghu doesn't hear from Lekha again and is heartbroken, thinking that she has dumped him.

Four years later, Raghu receives a call from Lekha, who tells that she is with Thiru, who is in trouble and further asks him to arrive at Mumbai to help him. Raghu arrives at Mumbai, and learns that Thiru is actually an undercover cop, who is on a mission to expose an illegal arms deal, and is now on the run as the cops are after him. Thiru is arrested and taken to the court, where the cops and goons attack him. Thiru and Raghu, who arrives there on the behest of Thiru's senior Arun Bhide, subdues the attackers and Thiru escapes without seeing Raghu. Raghu finds the location where Lekha had asked him to arrive and finds her held at knifepoint. He rescues Lekha by defeating the goons and get into an auto, where Thiru appears and the brothers reconcile. However, the auto is attacked and Thiru is killed in the shootout, leaving Raghu devastated.

Before the auto was attacked, Thiru had given a keychain to Raghu and asked him to keep it safe. Lekha then narrates what happened after Kuberan took her from Raghu's house. Kuberan wanted Lekha to act in more films against her interest and to make her accept, he thrashed his son and wife, where she finally agreed to act out of fear for Raghu and his family. Kuberan takes her to Mumbai where he pimped her to other actors, but she is rescued by Thiru. One day, Thiru asked her to accompany him and visited a gym and a few other places. It was during this time that Lekha had contacted Raghu. Raghu takes Lekha to his college senior Mythili's room, in order to keep her safe.

Kuberan learns about Lekha's location and arrives with DCP Nagaraj to take Lekha away, but Raghu thrashes Kuberan and stabs Nagaraj (who was the person behind Thiru's death), where he escapes again with Mythili and Lekha and tries to clear his brother's name. Raghu visits the gym that Thiru had visited, but finds the locker to be empty. The cops arrive with DCP Suraj, who actually got Thiru embroiled in this problem, and arrest Raghu. In the meantime, Kuberan arrives after finding Lekha's location and takes Lekha and Mythili. Raghu is taken to a room, which is revealed to be Thiru's safe house, where he attacks the cops before being shot by Nagaraj. However, One of the cops shoots Nagaraj and the room is locked.

Having been saved by the keychain, Raghu discovers a table which has a keyhole that matches with the key Thiru had given him (the keychain was actually a key) and finds a hard drive and a laptop, which reveals about the illegal arms dealings done by many influential people, including Kuberan. Raghu calls Kuberan and arranges a meeting to provide the hard disk. The cops arrive as well and Raghu shoots all of them dead. Thiru's name is finally cleared and those involved in the dealings were arrested. Raghu arrives at his sister's wedding with Lekha and Mythili. After secretly performing Thiru's last rites, Raghu tells his parents that Thiru is doing well and that he is a cop. In a voice-over, Raghu narrates that he will hunt down the persons, who are also involved in Thiru's death.