Unnai Solli Kutramillai is a Malayalam film. Balu (Karthik) is a graduate youth, came from his village to town, who want to become rich. He works as a police informer and fall in love with Janaki (Sithara), the daughter of Inspector Veerapandian. Veerapandian asks Balu to watch closely his daughter if she had a boyfriend. In the same time, Veerapandian's ennemy Kumar (Nassar) tries to kidnap her daughter, they fail due to his opposition. Balu finds an illegal drug trade and his house's owner was sent in jail, then his all family commits suicide. Veerapandian is promoted as assistant commissioner and Balu resigns his job. One day, Veerapandian finds Balu in a crime scene and asks him to say who's the killer but he refuses. Even beaten, he says nothing and he cannot find a job. Baby is killed and Balu decides to steal the money from criminals. Balu becomes rich and Kumar falls in love with Balu's sister Parvathi. Balu was later arrested by Veerapandian and Kumar refuses to save him, his sister realises that she has been cheated by Kumar and Kumar kills her. Janaki tells that the culprit is Darmaraj and Veerapandian releases him. Balu kills Kumar and Darmaraj to revenge his sister death.