Vikram , Abitha , Sivakumar , Sriman
Sethu (Vikram) is a rough and macho college rowdy and also The Students Union Chairman of the college, who uses violence as the only way to deal with people. He lives with his brother, a Magistrate(Sivakumar), and his sister-in-law, who is the only person who seems to understand him properly.
The movie opens with Sethu winning the elections to the office bearers of the colleges Students Union followed by celebrations and in-campus fight between the rival candidates.
Sethu is called as Chiyaan (the meaning of this word was unknown until the director Bala in an annual function of the Tamil Department of The American College, Madurai told to the audience that Chiyaan means a street-smart rogue), a pet name given to him by his friends. Sethu has a staple diet of yes-sir friends surrounding him. He comes across a timid girl, Abitha, who is the daughter of a poor temple priest, and starts to woo her. When she initially rejects him, he kidnaps her and forces her to fall in love with him.
When the girl falls in love with him, Sethu is attacked by brothel goons and ends up in a swamiji ashram with brain damage. With Sethu with no memory of his past and his unusual behaviour he starts to recollect memories. At one point, he is completely back to his normal self and tries to escape by climbing over the gates. Unfortuntely, he fails and ends up with serious injuries.
Whilst sleeping with his injury, Abitha makes a surprise visit. However Sethu is asleep and she leaves with this woeful memory of him. As she is about to leave the institution, he wakes up and realises that she had come to see him. As he calls out, she leaves unable to hear him.
Persistent to meet her he makes another attempt to leave the institution and this time he is successful. When he arrives at her house he is presented with his love unfortuately dead. He realises that she had committed suicide.
Distraught after what he saw, he just walks out and at that point he is met with the mental institution wardens who came chasing after him. The film ends with Sethu leaving with them as he has nothing to live for after his true loves death.