Naachiyaar (Jyothika) is a tough policewoman in Chennai who is put in charge of solving an underage rape case. She tracks down a pregnant Arasi (Ivana), the victim, from her uncle and his goons who plan to get her an abortion. Although Naachiyaar saves Arasi, her uncle and his friends escape and go into hiding. Meanwhile, Naachiyaar's partner, Feroz arrests the suspect, Kaathu (G.V. Prakash Kumar). He is then sent to a juvenile home, where he tells his story to one of the wardens, who is soft-hearted towards him.