Karunakaran finds it difficult to adjust with the society that surrounds him, and his unpredictable bursts of anger turn into a constant source of worry for his mother and brother. A chain of troubling incidents pushes him out of Madurai and into the crowded streets of Chennai, where the city’s rhythm challenges him in new ways. Even though he shines academically, he ends up enrolling in a local arts college in the city and rooms at a hostel, where the pressures and temptations of youth begin to mount. In this unfamiliar setting, Aarthi, a medical student and the younger sister-in-law of Karunakaran’s sister, begins to look at him with sympathy and a growing softness.
At the same time, Marimuthu, an ACP, alongside Inspector Rajendran, SI Selvam, and HC Perumalsamy, witnesses a car accident on the outskirts of Chennai. They stumble upon a substantial stash of cash, and, in a moment of moral compromise, kill the half-dead victim and flee with the money. The truth starts to unravel when Maya, a street-side listener, overhears Marimuthu’s telephone conversation and records it. She plans to use the information against him, but in a twist of fate, her camera with the evidence goes missing. The next day, a threatening call confirms Maya’s involvement in recording the conversation, and an enraged Marimuthu turns his anger on Maya, ultimately killing her.
A sincere cop named Palaniammal steps in to take up the case, determined to see justice done. In Karuna’s college hostel, a wave of thefts begins to surface, and Marimuthu learns that one of the students has stolen Maya’s camera. A bag containing all the stolen items is found in Karuna’s hostel room, casting him as the prime suspect and leading to his arrest. Marimuthu, with his associates, abducts Karuna and Maya’s friends with plans to kill them in a forest. They carry out the killings of Maya’s friends, but Karuna manages to escape and makes his way back to Chennai. In a cruel twist, Marimuthu discovers that Karuna did not actually threaten him; instead, Karuna is falsely accused of mental instability and is institutionalized.
Karuna is kept under constant sedation by a corrupt doctor, and the authorities manufacture a story that he suffers from a mental disorder and believes he is being pursued by a group of policemen in a fake encounter. He eventually escapes the mental asylum and returns to his hostel, where he kidnaps Rajendran and pressures him to reveal the truth to the public. Palaniammal gathers crucial information and pieces together the real motive: the thief who stole Maya’s camera is Dinesh, the son of the college principal, who exploited the chaos to hide the stolen items in Karuna’s room during vacation, hoping Karuna would be blamed and the matter would vanish.
When Palaniammal confronts the culprits in the college’s old auditorium, a call from the commissioner adds a political layer: the person Marimuthu murdered was a leading Bangalore politician, and exposing the truth could trigger larger state-level problems, so the incident is kept from the media. Palaniammal’s options become limited, and the situation remains tense. In the end, Karuna erupts in fury and eliminates Marimuthu, Rajendran, Selvam, and Perumalsamy, a act that leads to his return to institutional care as a consequence of the earlier false mental-health conviction. After his eventual release, Karuna marries Aarthi, and the pair settle into a quieter life as he begins work as a teacher in a deaf-dumb school, choosing a path of ordinary service after the storm.
