Trama

Gang leader Sakthivel adopts Amaran after saving him during a gang war. Years later, Sakthivel survives an assassination attempt and suspects Amaran's involvement, leading to a conflict of loyalty and revenge.

Rangaraaya Sakthivel "Sakthi" (Kamal Haasan) is in a green field, facing somebody in a fight, describing his relationship with Lord Yama, who killed his mother when Sakthi was young, from when he had become a thug and a one-man Yakuza.

In 1994, in Old Delhi, gang leader Sadanand Yadav (Mahesh Manjrekar) meets with rival kingpins Rangaraaya "Manickam" Manickavel (Nassar) and his younger brother and co-leader Rangaraaya "Sakthi" Sakthivel to discuss a truce between them after years of rivalry. However, unknown to Manickam and Sakthivel, Sadanand later invalidates the truce by orchestrating a shootout involving the Delhi Police. The ensuing tussle results in the death of a newspaper deliveryman Muthuraman (Elango Kumaravel) caught in the crossfire when he is unknowingly shot by Manickam, leaving his children, Amaran (Silambarasan TR) and Chandra (Aishwarya Lekshmi), separated. Sakthivel believes Amaran shielded him during the chaos. Moved by the incident after learning that Amaran's father was the newspaper delivery man, Sakthivel adopts him and raises him as his own son, while promising Amaran that he will find Chandra.

In 2016, Manickam's daughter, Shanthi (Alisha Rahman), dies by suicide after being cheated by Sadanand's nephew, Ranvijay Yadav / Raanu (Rohit Saraf). Shanthi was pregnant but Raanu refuses to acknowledge the baby as his own and wants nothing to do with Shanthi, leaving her no choice. In retaliation, Amaran captures Ranvijay, who Sakthivel kills. As a result, Sakthivel is imprisoned, leaving Amaran in charge of the empire.

Indrani is Sakthivel's mistress and comes often to meet him inside prison. Sakthivel rescued Indrani from a dance bar when he was looking for Chandra. Indrani was forever indebted to Sakthivel for his generosity.

Later, Manickam and Amaran meet Sadanand, who proposes a peace deal again: he will enter politics, and Amaran can take over his business territories. Though initially displeased, Sakthivel eventually accepts the arrangement and is released from prison. Amaran argues that this is the only way that the guns would fall silent between the clans. Sakthivel's daughter Mangai is in love with henchman's son Naaga, who is from a different caste. Mangai begs Amaran to get her married to Naaga before Sakthivel comes out of prison.

Upon his return, Sakthivel approves of his daughter Mangai's (Sanjana Krishnamoorthy) relationship with Naaga (Adithya Krishnan R), son of his henchman Sivaguru (Tanikella Bharani), and arranges their wedding. During the ceremony, he observes the shifting dynamics of his empire, with everyone now treating Amaran as the leader, concerning him as he thinks Amaran might overthrow him. At the wedding Amaran meets Indrani for the very first time. Amaran admits that he has feelings for Indrani, but she rebuffs him.

While traveling with his gang, Sakthivel narrowly survives an assassination attempt by henchmen of Deepak (Ali Fazal), Ranvijay's older brother, who swears to avenge his brother's death by finishing Sakthivel, despite Sadanand's reluctance due to their deal. Sakthivel is admitted to the hospital, where he meets Inspector Jai Royappa / Jai (Ashok Selvan), who tries to ask him about the gang war.

After the incident, Sakthivel begins to suspect Amaran, due to his absence during the attack, and eventually confronts him, deeply unsettling Amaran. Sakthivel's wife Jeeva (Abhirami) tells him that Amaran was with them at that time and Mangai was pregnant, but she ended up in miscarriage.

Meanwhile, Manickam and others in the gang, Anburaj (Bagavathi Perumal), Kahlua (Arjun Chidambaram), and Pathrose (Joju George), become wary of Sakthivel's constant suspicions of them and his interference in the gang's operations, and decide to overthrow him. They manipulate Amaran by falsely claiming that Sakthivel was responsible for his father's death during the 1994 shootout, convincing him to join their plot. Anburaj says that Sakthivel knew that the man behind the door was not a cop, but a newspaper delivery person, and yet he shot the person through the door. Amaran is shocked as Sakthivel had told him that he shot his father thinking he was a cop.

Seeking peace, Sakthivel travels to Hilsa, Nepal (on the way to Mount Kailash) with them, unaware that another assassination attempt awaits him. Amaran joins the conspirators and throws Sakthivel off a cliff, believing he has killed him. Upon returning, the gang declares Amaran as the new Sakthivel. However, it is revealed that Sakthivel has survived the fall and heads towards a nearby Buddhist monastery, narrowly escaping an avalanche.

Two years later, Sakthivel returns to Delhi, cold, calculated, and vengeful, having learned martial arts from Nepali monks to aid in his quest. He learns that Jeeva has suffered traumatic memory loss due to the hysteria of learning about his supposed death and the subsequent manhandling by Manickam. Sakthivel then travels to Tiruchendur, where Jeeva and Mangai now live, and gets distraught upon seeing his wife in a pitiable condition to the point that she is unable to remember who he is, prompting him to avenge his betrayers.

Sakthi then proceeds to eliminate them one by one: he kills Anburaj by pushing his head against a helicopter's rotors, Pathrose by pushing him in front of a running train, and Manickam by shooting him and pushing him off a bridge. Only Amaran and Kahlua remain. Kahlua surrenders to Sakthivel and acts as his spy to track Amaran. However, Amaran soon discovers this and kills him.

Sakthivel meets Inspector Jai Royappa, making a deal with him that Sakthivel will give all the important political and business contacts to Jai to expose corruption, while Jai will let Sakthivel kill Amaran, for his revenge.

Meanwhile Sadanand Yadav passes away and upon his death, Deepak returns to Delhi to take over Sadanand's political and criminal empire.

Sakthivel later contacts Indrani (Trisha Krishnan), his mistress, who is now with Amaran in a one-sided relationship. However, Deepak kills her in a controlled bomb blast made for Amaran, devastating both Sakthivel and Amaran. While trying to save her, Sakthivel is injured when a ceiling collapses on him. He is rescued by Inspector Jai Royappa and taken to his house.

During his recovery, Sakthivel is treated by Dr. Anna, who is revealed to be Amaran's long-lost sister, Chandra - the one separated during the 1994 shootout. Sakthivel summons Amaran to the location of the original shootout. There, the two engage in a one-on-one fight.

As the battle ends, Sakthivel convinces Amaran that he was not responsible for his father's death, making Amaran realize his mistake, while Chandra arrives at the scene with Jai after having learned of her long-lost brother's whereabouts from Sakthivel. Just when Amaran and Chandra are about to reunite as siblings, Deepak intervenes and fires a shot at Amaran. Sakthivel shields him, but the bullet fatally wounds Amaran. Sakthivel kills Deepak and tries to revive Amaran, but he dies from his injuries, with his last words being "My little Chandra.", leaving both Sakthivel and Chandra devastated. Sakthivel later reflects on how death has haunted him throughout his life taking his mother during childbirth, his elder brother through betrayal, and now Amaran, who was like a son to him.

Years later, Sakthivel, now a farmer, in the same field, shown in the beginning, and having given up his gangster life, lives with Jeeva (who still does not recognize him), Mangai, and others peacefully in a village with their young grandson, also named Sakthivel. The film ends with Jeeva fondly calling her grandson "Dei Sakthivel" (Hey Sakthivel), the same affectionate term she once used for the elder Sakthivel.