Chanthupottu movie tells the story of Radhakrishnan (Dileep) an only son, who is brought up like a girl by his grandmother (Sukumari) who wanted a granddaughter. He is known as Radha. He dresses like a girl, wears makeup, thinks and behaves like a girl.
He is comfortable with his identity till he came across Mallu ( Gopika). This young girl confesses that she is in love with him. Mallu, a friend for so long, now becomes his fiancee.