Vetrivel, an undercover IPS officer, is chased along a windswept coastline by a gang of heavily armed men. He uses his martial arts prowess to neutralize several attackers, but a helicopter rescue attempt goes awry when he is shot from a hanging ladder and washes up unconscious on a Goa beach. He is found and brought to Shirley, who escorts him to her doctor aunt, Sowcar Janaki.
Upon waking, he realizes he has amnesia and only fragments—visions of sculptures and a karate class that feel oddly familiar. Meanwhile, a local rowdy has been harassing Shirley and her niece. The fighter within him quickly asserts itself, easily repelling the next attack, convincing him he might be trained in martial arts. To protect her, the doctor urges him to marry her niece, Jaya. He agrees, and at their wedding he fends off another attack.
With a new wife in tow, he travels to Madras to locate his identity. They learn that the earlier flashes are linked to the sculptures in the Connemara Hotel, and that he used to be a regular there. Extracting a bank account number he had used, they visit the bank and discover a locker filled with a large sum of money, multiple passports, and a handgun.
Leaving the bank, an unknown assailant attacks him in the lift; he maims the attacker and escapes, leaving a shocked witness behind. He contemplates surrendering to the police, but his wife convinces him to keep going.
Vijay and Jaya are part of a wedding band, and Vetri teams up with them to uncover another flash. In a dance class, the instructor recognizes him and guides him toward the singer, Disco Shanti, who hints that he is in danger. When a new wave of attackers strikes, Vijay and Vetri fight side by side to rescue [Jaya], and Vijay pledges to help Vetri in his quest.
Vetri visits the singer, but is shot again; the singer helps him escape and hands him a contact number to reach, leading him to [Nithyanandam], the Deputy Inspector General of Police. There, he learns the truth: his name is indeed Vetri, and he was once married to Lalitha. He had been an undercover officer who collaborated with the DIG to bring down the notorious hit man Zinda. The plan had been to let Zinda contact Vetri, but the mission goes awry when Lalitha is abducted and subsequently shot, forcing Vetri to break cover to protect her; she dies in the struggle, and Vetri is forced to flee once more.
Vetri pieces back the fragments of the past and unravels Zinda's plan to assassinate Baba Appaji, a revered priest Baba Appaji when he meets the singer. Vetri and Vijay thwart the attempt, but Zinda escapes. Zinda abducts their wives and uses a photo to taunt them, prompting a race to locate Zinda's lair. Vetri and Vijay corner Zinda’s gang aboard a port ship; Zinda triggers a bomb, but the two men work together to disarm it and arrest Zinda, ending with a firm handshake as the case closes.
