Mersal

A series of abductions of medical staff unfolds at dawn, including an ambulance driver, a medical broker, a hospital worker, and a surgeon. The pattern points to Maaran, and he is arrested and interrogated by DCP Randy as investigators close in.

Maaran earns trust by treating patients for just 5 rupees, earning enormous local support in Chennai. His selfless care earns him an award in Paris from doctor Arjun Zachariah, signaling his rising stature.

During his Paris years, Maaran performs as a magician and falls for Pallavi, Arjun Zachariah's assistant. In a controversial magic act, he kills Arjun Zachariah, attracting the notice of DCP Randy who begins an official investigation.

Daniel Arokiaraj arrives at the murder scene and pressures Randy to uncover the killer, hinting at corrupt motives and complicating the case. The murder investigation becomes entangled with politics and money in Paris.

Maaran returns to India and meets Tara, a news reporter, with whom he soon falls in love. Their relationship adds a personal dimension to Maaran's life as he faces the mounting mystery surrounding the disappearances.

In a key revelation, Maaran explains that the four abducted individuals were complicit in greed-fueled medical negligence and the deaths they caused. He provides the hostage locations and warns that timely hospital access could save the captives.

A past sequence shows Daniel viewing Maaran's affordable care as a threat to his hospital empire and ordering Maaran killed. Maaran is beaten by Daniel's goons but is saved by his doppelganger Vetri, revealing that the real crimes were later carried out by Vetri.

Vetri survives the assault and is raised by their paternal uncle Vadivu. Salim Ghosh later adopts Vetri and Vadivu, and Vetri learns magic tricks that fuel his desire for vengeance.

Maaran reconciles with Vetri and they swap identities, placing Vetri (as Maaran) in custody while Maaran hides in plain sight in the medical world. Daniel watches with opportunistic eyes, while Sesha plots a predatory bargain.

Daniel's nephew Sesha makes a reckless deal with Vetri to shut down the practice, but the truth comes out and Vetri slits Sesha's hand. Vetri then escapes custody using his magic tricks, while Maaran is rescued from danger.

Vetri defeats Daniel's henchmen and fights to the death, injuring Daniel during the clash. Maaran revives Vetri with CPR, and in the ensuing struggle Kasi is killed and Daniel meets a brutal end by Vetri's electrocution.

Vetri delivers a public statement exposing corrupt medical practices and embezzlement, declaring his ongoing mission to reform the system. He is briefly arrested, then, spurred by news of another tragedy, escapes using his magic to continue his mission.

With the dust settled, Maaran becomes the head of the Indian Medical Council, signaling a shift toward reforms and accountability in healthcare. The promotion marks the start of a broader effort to clean up the system, even as Vetri continues his vigilante mission from the shadows.