Plot
In 2014, Varadarajan, a cloud architect, develops software for hospitals to digitise medical records. After a tiring day, Varadarajan gets behind the wheel to head home. However, due to tiredness, he accidentally hits a bike carrying a couple and an infant. Rajendran, an ambulance driver from a hospital in Pallikaranai, arrives at the scene and recognises Varadarajan, whom he had seen earlier that morning. Together, they rescue the critically injured couple and rush them to the hospital. To protect Varadarajan from legal repercussions, Rajendran tells the police that it was a hit-and-run accident. Meanwhile, a grieving father is devastated upon learning that his child was stillborn. Moved by the father's pain, Varadarajan and Rajendran decide to give the infant they rescued to him. The father is overjoyed, and Rajendran feels relieved that he has saved Varadarajan from trouble, but Varadarajan believes that justice will be served eventually, no matter how delayed.
In 2023, Anand, the elder son of Professor Sivasubramaniam, is seen drowning his sorrows in a bar, lamenting his recent breakup. Sivasubramaniam views him as irresponsible and useless. Anand's life takes a downward spiral after his lover's suicide, leading him to excessive drinking. One incident where he creates a scene in front of his younger brother Prakash's prospective in-laws prompts Sivasubramaniam to curse him.
Meanwhile, Dhivya, who suffers from borderline personality disorder, is struggling to find a suitable groom due to her condition. Anand gets admitted to a rehabilitation center, and after a few months, Sivasubramaniam arranges for Anand to marry Dhivya, despite knowing about her disorder. At the wedding, Venkat, a lawyer and Anand's friend, suspects that Dhivya's behaviour is abnormal and advises Sivasubramaniam to call off the marriage. However, Sivasubramaniam refuses. Anand, aware of Dhivya's condition, wholeheartedly accepts her as his wife. They start their new marital life together, and Dhivya becomes pregnant. She gives birth to a baby boy at Bethel Hospital.
However, after some time, Dhivya notices that the infant given to her is not the same one she saw during delivery. Despite her protests, no one believes her, attributing her concerns to her mental illness, and Dr. Mahimaiammal, the chief doctor at Bethel Hospital, reviews the medical records and concludes that Dhivya's claims are a result of her postpartum psychosis, dismissing her allegations. Believing his wife's claims, Anand seeks police assistance to investigate the alleged baby swap. However, Dr. Mahimaiammal, after reviewing the hospital's video footage, denies any wrongdoing. The police suggest that Anand needs concrete evidence to support his claim. With Venkat's help, Anand conducts a private DNA test, which confirms that the baby they're caring for isn't theirs. The case is assigned to Sub-Inspector Chinnasamy, who's set to retire in three weeks.
As the investigation unfolds, Anand and Chinnasamy follow several leads, including a human sacrifice spot, but Anand rescues a baby that isn't his own. They also interview Dr. Punithavathi Rajasekhar and nurse Shailaja, but no clues surface. Their investigation takes them to a prison, where they meet a convict who leads them to Gajaa. They scrutinize the hospital's CCTV footage, where Chinnasamy notices a 20-second discrepancy, and Anand spots an elderly woman carrying two jute bags, one containing a baby. Anand follows the woman, who hands the baby to Sekhar. Anand confronts Sekhar and his men, and with Chinnasamy's help, they apprehend Moorthy, who was attempting to collect the baby. Initially, Moorthy, the elderly woman, and Sekhar refuse to cooperate with the investigation. However, Chinnasamy discovers that nurse Shailaja has an identical twin sister, unknown to the world. Using this information, Chinnasamy uncovers the truth: Moorthy, who runs a nursing agency, had lured Shailaja with a job offer in Dubai and instructed her to swap Anand's child with another baby from a government hospital, with the help of her twin sister and the elderly woman.
With this new evidence, Anand reluctantly hands over the baby they've been caring for to its biological mother, despite Dhivya's objections. Moorthy then reveals that he was supposed to hand over the abducted babies to Rajendran, who now owns a security service operating in the hospital. Before Anand could confront Rajendran, Rajendran is attacked by a group of men. Anand intervenes to save him, but the goons kill Rajendran after giving Anand alcohol. Anand suspects that Gajaa's men are connected to Rajendran's murder, noticing a similar tattoo on the killers. When Anand is beaten by Gajaa's men, his suspicion is confirmed. In a fierce fight, Anand overpowers Gajaa's men, and Gajaa reveals that he was hired by Varadarajan to kill Rajendran. Gajaa's revelation sheds light on Varadarajan's past. After the 2014 accident, Varadarajan allied with Rajendran to abduct babies and sell them to childless couples. Varadarajan's modus operandi involved using multiple layers of operatives, keeping his and Rajendran's identities hidden. As a software firm owner providing solutions to hospitals, Varadarajan gained access to sensitive data, which he exploited to abduct babies and sell them.
In Anand's case, Varadarajan was promised a hefty ransom of ₹2 crore by a US diplomat couple, who sought a baby born at a specific auspicious time, citing astrology. Gajaa also revealed that Varadarajan had ordered him to kill Rajendran, fearing that Rajendran might turn approver. Meanwhile, the US diplomat couple meets Varadarajan at a temple, coincidentally, where Dhivya and Anand have also come. Dhivya immediately recognizes her baby in the couple's arms and informs Anand. Anand confronts them, beats Varadarajan and retrieves his baby. Rajendran's son, fueled by revenge for his father's murder, stabs and kills Varadarajan. This twist of fate indicates Varadarajan's earlier statement that justice will be served, even if it's delayed.
