Maargan

Ramya is murdered late at night by an intravenous chemical that leaves her body numb and unresponsive. Dhruv arrives in Chennai from Mumbai to unofficially take over the investigation, bringing Inspector Shruthi and constable Kaali into the case. The case immediately shows parallels to an earlier tragedy, prompting Dhruv to push for answers.

Dhruv begins the inquiry with Ramya's boyfriend Karthik, a photographer who is about to work on a Rajesh-directed feature. The pendant chain Ramya wore is missing, and Karthik says it was a gift from a friend with no further details. The missing keepsake becomes a key thread in the unfolding mystery.

A hooded young boy is captured by surveillance cameras near the crime scene at night, but his face is obscured and cannot be identified. The glimpse raises suspicion of a potential accomplice or an eyewitness. The team treats it as a crucial lead to pursue.

Dhruv spots the same pendant design drawn on a dusty car and collects fingerprint samples for analysis. The forensic results point to Tamilarivu, a swimmer who was previously booked in a drug smuggling case. Tamilarivu becomes the primary suspect in Ramya's murder.

Tamilarivu is apprehended and kept in an isolated room for questioning. He drinks excessive water, chants hymns, and demands the pills he has been taking as the interrogation escalates into violence before he collapses faintly.

Tamilarivu tells Dhruv that he is trying to forget memories of his ex-lover Ramya, who left him in the past. He insists he has no connection to the murder Dhruv is pursuing. Dhruv notes the tension between memory, trauma, and motive in the case.

Dhruv pressures Tamilarivu to draw the pendant diagram and trigger memory recall. To retrieve memories, Tamilarivu jumps into the water and holds his breath, an extremely risky procedure. After resurfacing, he recalls the pendant's shadow in the water, providing a crucial clue.

Using Tamilarivu's hint, the team retrieves CCTV footage from an aquarium shop near the crime scene, which confirms Tamilarivu's innocence. Dhruv then urges Tamilarivu to help solve Ramya's murder using his extraordinary memory. Tamilarivu is initially hesitant but is moved when Dhruv shares his own tragedy.

Dhruv opens up about his daughter's murder and his own poisoning, making Tamilarivu feel understood. The memory coaching proceeds with safety and consent, and Tamilarivu agrees to cooperate to rewind his memories further. This alliance marks a turning point in the investigation.

Tamilarivu's revived memory points to a location in Kovilambakkam, though an owl disturbing his recollections obscures the killer's face. The search shifts toward this suburban area with new urgency. Dhruv and team narrow suspects based on location and timing.

Dhruv and Kaali enlist sanitary workers and a blind girl who heard the owl's call to gather new leads. They suspect a team of North Indian drug dealers may be involved and push to close in on the criminals. The investigation expands beyond Ramya's circle.

Akhila, Tamilarivu's sister, goes missing while Dr. Shalini, a cosmetologist, is murdered. The fear of retaliation intensifies as Vennila starts to emerge as a new potential victim. The threat shifts the investigators' attention toward the film industry connections.

Shruthi secretly installs a spy camera on Vennila, a model who has faced skin tone decisions in the industry. Vennila's backstory unfolds: she underwent skin-lightening procedures at Rajesh's urging, fueling a growing grudge against Ramya and the industry. The case ties fashion, casting, and revenge together.

Megha is revealed as Vennila's true identity, driven by trauma over skin color and rejection. She admits killing Priya and Ramya, and she plans to target Sana Trivedi next while also killing Dr. Shalini. Dhruv arrives just in time and shoots Megha, saving Sana; Karthik mourns the industry’s bias that fueled Megha's downfall.