Vinod (Dhanush), who has grown up under the care of a church father (Nagesh), is an introvert but a genius. He is forcibly sent to college by the father but is a complete misfit in class. Though shunned by the rest of his class, Divya (Sonia Agarwal) becomes his friend and he gradually warms up to her. His feelings soon turn into love but he realizes that Divya considers him as only a friend and learns that Divya is in love with another classmate, Aadhi (Sudeep Sarangi).

Divya's father is enraged on learning about her love. He locks her up and prevents her from contacting anyone. Vinod comes and requests to meet her on the pretext of getting some old clothes for himself to wear. Pitying Vinod, her father allows him to meet Divya. Vinod escapes with Divya and convinces her that she will meet Aadhi at Ooty.

Vinod has set up a secret place in Ooty for executing his plan of wooing Divya. He makes her stay with him, while convincing her by talking about Aadhi's arrival. On one such day, he reveals his miserable past, when he was made to work for paid labour after being orphaned at an early age. He revolts against the oppression one day. Promptly he is beaten black and blue for his profanity. Moreover, he also loses his girlfriend to rapists in that place, who also kill her. After some days he kills the woman running the orphanage and also kills the rapist, helped by other children. They manage to break the place and escape from there and seeks refuge in the place of a church father.

Divya is touched by his past. Incidentally the police and Aadhi arrive at the place. While Vinod was away to get some food, they try to explain to Divya that Vinod is a psychopath. Yet Divya scoffs at their claims, citing his gentlemanly behaviour over the days she has been alone with him. Vinod, learning that the police have arrived at the scene, begins to indulge in violence. He opens fire, killing a police constable. Forcing them out of their hideout, he manages to evade the police Inspector and Aadhi and successfully brings Divya back to their original place of stay.

Divya soon identifies the tiger in the cow's skin. Vinod pleads with her, telling her that all he wanted in his life was her presence. But Divya called him a friend and stated her inability to accept him as her partner for life.

Meanwhile, Aadhi regains consciousness and comes back to attack Vinod and rescue his girlfriend. A violent fight follows, where Vinod defies his puny self and treats Aadhi with disdain. The fight culminates with Vinod, Aadhi and Divya teetering at the edge of a slippery cliff.

While Divya clutches a tree bark tightly, Vinod and Aadhi slip out and barely manage to hold either of her hands. Divya is forced to choose between her boyfriend and friend. Aadhi's pleas notwithstanding, Divya does not have the heart to kill Vinod, who smiles wryly at Divya and lets go of her hands himself, falling to his death in the abyss.