Villupuram-based engineering graduate Yazhini Bakthirajan, leaves for Chennai against her parents' wishes to pursue a career in the IT sector. When the company she works for shuts down suddenly five months later, she faces financial hardship and is forced to move into a low-cost housing colony while searching for a new job, where her neighbour Kathiravan resides.

Kathir is a rowdy who works for a local area councillor Thilagar, whose only aim in life is to own a bar of his own. He had just been released from prison after serving a five-year sentence for taking the blame for a crime he did not commit on the orders of the councillor. Kathir did the deed on the promise that his status within the councillor's gang will be elevated once he is released, but the promise was reneged. Though both of them dislike each other in the beginning, they gradually warm up to each other despite their different backgrounds and become a sort of symbiotic support system for one another.

Facing pressure from her family over her career and wedding, Yazhini introduces Kathir to her parents as her boyfriend who is a successful manager in an IT firm. Her parents decide to fix their marriage but change their mind after seeing Kathir thrashing two men opposite a temple, realising that he is a rowdy. They bar Yazhini from returning to Chennai, even forbidding her to attend an important job interview. Meanwhile, Kathir starts a gang war by beating up the henchmen of a rival gangster Moda Kumar. The councillor decides that Kathir should murder Kumar. After ensuring that Yazhini attends her interview, Kathir proceeds with the plan to murder Kumar. However, during the ensuing scuffle, Kathir ends up being stabbed with a rebar and is left to bleed to death.

Two years later, Yazhini has become a director in her company and has moved out of the housing colony. She constantly thinks about Kathir, whom she had never seen again after her interview. Yazhini yearns to show Kathir her new life, knowing that he is the one person who will be happier than even herself in her having achieved her dreams. She soon finds Kathir working at a petrol bunk, having survived his murder attempt and abandoned his rowdy past. The two rejoice in the happy ending.