Madhu movie is about a young boy named Madhu (Ramesh) who roams in the bike. Mercy (Priyamani) and Esther (Janavi) who are two friends in the hostel. Mercy is a kind and humble girl to others. She belives in Jesus. Esther who is a total opposite girl compared to Mercy. She is a girl who dresses glamourasly. Esther tease eveyone.
Once Madhu kisses Esther in public. Madhu oten meets Mercy in the Hostel. One day he expresses his love to her. But Mercy refuses to his love. After Mercy finished her Examination, and because it was her vacation Mercy went to Mahi her home town. Madhu follows her all the way to Mahi. Mercy's father Siluvai encourages mercy to have a good position.
Soon Siluvai's favorate becomes Madhu. He disturbs Mercy in the name of love. Esther comes to know about their affair and her charecter changes after that. Siluvai comes to know about their affair.