Meera, Trisha Krishnan, lives a peaceful life with her husband Anand, Santhosh Prathap, a wildlife photographer, and their son Kavin Saathvik. During pregnancy, the family plans a road trip to Kanyakumari for Kavin’s birthday, a celebratory journey that would bring them closer. On medical advice, Meera decides to skip the trip and asks Anand to continue the voyage with Kavin, hoping to protect both mother and child.
Tragedy strikes when Anand and Kavin die in a road accident, colliding with a car driven by businessman Gangadharan Ajith Koshy, who was en route to Chennai. At the hospital, Meera’s world collapses as she learns of the loss; Uma, Meera’s friend, and Uma’s husband Prasad rush to deliver the devastating news. Overwhelmed by grief, Meera slips into unconsciousness, and in a moment of despair she attempts to take her own life. Uma’s timely intervention prevents a second tragedy, but the emotional damage leaves Meera broken and seeking answers.
While Meera and Uma search the accident site, they encounter Kaaturosa Negha Shahin, who offers shelter at her home. Through Kaaturosa’s father, they uncover a history of accidents along the same stretch of NH 44, hinting that something systemic is at work. Meera reports the latest incident to sub-inspector M. Moorthy at Tirumangalam, who notes the absence of any solid trace at the scene, while head constable M. Subramani grows suspicious of the pattern.
Determined to understand why accidents arise only in a specific zone of the highway, Meera immerses herself in the investigation. At the police station, Sundar, Gangadharan’s son, contends that his father was not drunk, challenging Meera’s suspicions. She and Subramani consult Dr. Madhana Gopal, who prepared the autopsy report; following his guidance, they enlist forensic experts to probe for hidden clues, including alcohol traces in Gangadharan’s car. Although the forensic team detects caltrops on the tyre, there are no clear signs of alcohol.
The trail widens as Meera and Subramani locate Ponnudurai, who admits helping to inject alcohol into Gangadharan’s blood for money. They trace the money to Bhaskaran, who is connected to transferring funds. Bhaskaran reveals a larger, tightly woven secret network behind the accidents, including a shadow economy that finances and controls the routes. Uma explains to Meera how “dark banking” operates, funneling money through vulnerable accounts while the more powerful figures stay hidden. Meera realizes this network targets travelers on NH 44 to loot money and jewels, and that Gangadharan’s car was only a diversion or cover for something far more valuable.
Back in the investigation, Meera discovers that Kaaturosa’s husband, son, and Gangadharan were all brought to the hospital, and Kaaturosa herself witnessed the crash. She confesses the involvement of Prasad in the gang’s operations. Using coordinates obtained from Bhaskaran’s mobile, Meera and Subramani narrow the gang’s hideout, where they are ambushed and held hostage. Prasad arrives with the others, revealing his own complicity in the network as he explains his motives. Chella, the gang’s associate, attempts to silence Meera, but Uma unexpectedly appears with a gun and helps them escape.
Meera and Uma locate a house under Prasad’s control, where they realize he is the mastermind behind the whole operation, operating from a private number. Subramani phones Meera with news about Chella’s ally Mayazhagan, a college professor ten years earlier who was driven out of academia after a failed plea for help and been entangled in a local minister’s corruption plot. Mayazhagan’s fall spiraled into a cycle of vengeance, leading Chella to recruit a crime syndicate that targets the highway to kill and rob, consolidating power over the Kottai-Manga gang and recruiting Prasad along the way. From a laptop in Meera’s possession, they learn that Gangadharan’s supposed gold-smuggling scheme was part of a larger plan to move riches across NH 44.
Mayazhagan hatches a plan to strike at Arumai Chandiran, a benami minister figure who is rumored to be smuggling gold. According to Mayazhagan’s scheme, Chella and Prasad seize Arumai Chandiran’s car on the road and leave him behind. When Mayazhagan calls Chella, he realizes that Arumai Chandiran is not in the vehicle and there is no gold inside the car after all. He orders Chella to back off, but a subsequent explosion kills both Chella and Prasad. On a rescue call, Meera steps up to confront Mayazhagan, challenging him to come face-to-face.
The mystery thickens as Meera learns about Padma, also known as Padmapriya, Arumai Chandiran’s second wife and a key player in the smuggling network. Meera suspects Padma may have traveled to Kerala with a different plan in mind, given her lack of involvement in the ongoing scheme. Meera targets Padma, kidnapping her to Prasad’s house to uncover the truth. Mayazhagan tracks them down and injures Meera, but Padma’s past actions come back to haunt Mayazhagan: Padma had previously been linked to efforts to coerce him into a relationship and to frame him for harassment, a scheme that backfired on him. In a final confrontation, Padma’s revelations expose the long-buried schemes and motives behind the highway crimes, and Meera confronts Mayazhagan, ultimately ending his vengeful arc when she stops him from pairing violence with his memories.
