Bhaskaran Arya Boss is a cheerful, carefree youth in Kumbakonam who has yet to finish his B.A. degree, spending years writing arrear examinations. His only friend, Nallathambi Santhanam, owns a saloon that came to him as a dowry when he married a woman who was two months pregnant. During an arrear exam, Boss crosses paths with Chandrika Nayanthara Shanmugasundaram, a lecturer, and he is instantly drawn to her, even though she disapproves of him after he attempted to copy during an invigilated exam.
Boss lives with his widowed mother Sivakami Lakshmi Ramakrishnan, his elder brother Saravanan Subbu Panchu, and his younger sister Nithya, who is a college student. When Saravanan marries Nandhini Vijayalakshmi, Boss discovers that Nandhini's younger sister is Chandrika. Though Chandrika is older than him, he wishes to marry her. He proposes to her and she mocks him, but he remains resolute. When he approaches her family for the alliance, his unemployment is repeatedly mentioned, so he leaves his house to prove himself.
Boss faces many obstacles in his path to prove himself. He is insulted by Shanmugasundaram Chitra Lakshmanan, and he does not even have a place to live. After many difficulties, Boss, with the support of Nallathambi, establishes a tutorial centre for Class X students. Nallathambi gets money from Velpandi Rajendran, a local don, who signs an agreement that if his son Paalpandi Kumki Ashwin does not pass the examination, he will take Nallathambi's property and make him work in his cow dung place.
Velpandi reveals his family history: his father, in his Class X examination, forced his teacher to write the examination. Velpandi, during his own exam, wrote only four words in his paper with an aruval symbol, blackmailing the teacher into making him pass or risk being killed. Paalpandi sleeps in the examination hall, and if anyone tries to wake him, he will bite the teacher's hand. However, Paalpandi eventually starts to study and makes others listen in the class when Boss appoints a blind teacher. Despite early setbacks, Boss makes a very heavy profit on the deal, while his students top the examinations in the state and Paalpandi passes the examination with favourable marks. Velpandi tears the agreement, offers Nallathambi a huge amount of money with no interest, and appreciates him for making Paalpandi pass. It also convinces Chandrika to reciprocate his love. However, Shanmugasundaram opposes their marriage as revenge for not having sanctioned a loan to Boss.
Shiva Jiiva, a supposed teetotaller and the son of a businessman who is Shanmugasundaram's friend, is introduced as Chandrika's prospective groom. Boss then confronts Shiva, revealing to him that he loves Chandrika. The two get into a fight soon after, but when Shanmugasundaram arrives at the spot, he learns the truth: Shiva and Boss are now friends and the whole fight was just a drama set by Nallathambi. Shiva supports Boss and Chandrika. Under Shiva and Boss's orders, a disappointed Shanmugasundaram is forced to unite Boss and Chandrika. It is revealed that M. Rajesh called Shiva and told him to stop fighting and unite Boss and Chandrika.
