An ambulance driver, a medical-broker, a hospital HR and a surgeon, were mysteriously abducted at dawn. Alerted by the incidents, Ratnavel, a police officer with Tamil Nadu Police nabs the suspect. As the interrogation begins the suspect explains his motive, Maaran, popularly known as 5 rupees doctor, as he charges similar amount for treating patients from everyone, arrives for a medical seminar only to be mistaken at Paris Airport due to his cultural identity. After the seminar, Maaran displeases Arjun Zachariah, another doctor from Chennai, and his offer to team up with him, but develops mutual romantic feelings with his assistant, Anu Pallavi. He invites Pallavi and her nagging boss to his magic show, where Arjun is killed deliberately in presumed magic-gone-wrong, shocking his friend Daniel Arockiyaraj.After arriving back to Chennai, Maaran gets betrothed to Tara, a media anchor. When an autodriver's school-going daughter met with an accident, the treatment is delayed deliberately resulting in her death and suicide of her mother. With the help of Vadivu, the people behind this incident were abducted, tortured and killed. Deducing the events, Daniel's henchmen traps Maaran, but gets thrashed by Vetri (brother of Maaran), who body swaps Maaran and thus gets caught to the police and reveals himself as a magician who killed Arjun in Paris, for his inhumanely approach in medical profession. Vetri then escapes and convinces Pallavi. As Daniel reaches out to Maaran, holding Tara and Sarala as hostage to find the whereabouts of Vetri, the latter traces Vadivu and confronts Vetri. At the same time, Ratnavel reaches blind magician Salim Ghosh to know the truth.In 1970's, Vetrimaaran, a village wrestler marries Aishwarya, a Punjabi and comes back to his native place, Manoor (Madurai district) with his newborn kid (Maaran). He successfully chases out people who wish to build industry, and decides for a temple only to be thwarted by a fire accident resulting in death of two kids due to lack of hospital. When Vetrimaaran, Aishwarya and the villagers, finally decides to go for building a hospital, Daniel and Arjun were made as the chief doctors of the hospital and ownership also transferred. The hospital soon becomes famous for its free medical treatment to all. However, it soon turns out that Daniel and Arjun were crooks who were after money, and they perform a Caesarean section on Aishwarya when she was in labour with her second child with the intention of extracting more money from Vetrimaaran, even though she could deliver the child normally. While she is fast losing a lot of blood during the operation, that, along with an overdose of anesthesia, leads to her death, and the child was declared stillborn, before she spills the beans on Daniel and Arjun. Determined, Vetrimaaran was beaten to death by Daniel and his henchmen, who also shatter a glass bottle on his son's head, due to which Maaran is unable to recover what happened before he was hit on head; he was safely placed into a Chennai-bound lorry before Vetrimaaran's death.Meanwhile, the second child (Vetri) of Vetrimaaran did not turn out to be stillborn. He was adopted, and taught all the magic tricks from Salim Ghosh. As Maaran reconciles with Vetri, the police arrive and presumably arrest Vetri. However, when Daniel confronts Vetri in prison, it's revealed that he's actually Maaran, as the brothers switched places before the police arrived. Panicked, Daniel calls his nephew, Sesha, who went to threaten Maaran, who is actually Vetri. Vetri slits Sesha's wrist, who runs off, trying to get help. Daniel goes to confront Vetri, who gets hit by Kasi, Daniel's henchman who killed Vetrimaaran. He shows up with an unconscious Maaran. The two brothers, though, spring back up to life, and kill Daniel and Kasi together. Vetri is then arrested for his role in the murders, and sentenced to prison. Before going to jail, he declares that he would continue with the "cleansing process" until all doctors and hospital staff indulging in corrupt practices are eliminated. In prison, Vetri contemplates a television news report in which a young girl had died due to negligent medical treatment, before vanishing off.