Aegan

Shiva, a CB-CID officer, is tasked with foiling terrorist John Chinnappa's plans. He is also trying to reconcile with his estranged family members, including his father and half-brother, amidst ongoing complications. The mission involves protecting Ram Prasad, a police approver, and uncovering John Chinnappa's controversial ploys.

Karthikeyan, Shiva’s father and the police commissioner, assigns Shiva to attend St. John's College in Ooty to protect Pooja, Ram Prasad’s daughter, from her father's enemies. Shiva agrees reluctantly, acknowledging his inexperience with modern youth and their ways. His goal is to safeguard Pooja and locate Ram Prasad.

Shiva returns to college after many years, blending in with students as an older, undercover student. Despite being teased for his outdated style, he navigates college life while balancing his covert mission. He encounters quirky teachers and the college principal, Albert Aadiyapatham.

Shiva discovers that Narain, who is later revealed to be his half-brother, is Pooja’s best friend. Pooja is jealous of other girls’ attention towards Narain. Shiva begins to bond with Narain and Pooja, while also dealing with initial suspicions and misunderstandings.

John Chinnappa’s men kidnap Pooja, but Shiva intervenes and rescues her. To the students and teachers, Shiva becomes popular as he proves himself by protecting Pooja. He also starts developing feelings for Mallika, the chemistry teacher.

Narain admits to Shiva that he has been helping his father Ram Prasad, causing Pooja to feel betrayed. Pooja refuses to communicate with Narain, leading to emotional tension. Shiva learns that Narain is his brother, and his family’s backstory is explored through flashbacks.

Shiva takes a stand and arrests Ram Prasad when Pooja introduces him to Shiva as a criminal. This shocks Pooja and Narain, but Shiva remains committed to his duty. The family attempts to reconcile as Shiva prepares to confront John Chinnappa.

Shiva locates John Chinnappa’s hiding place and leads an operation to catch him. A fierce fight erupts between Shiva and John's men, culminating in Shiva killing John to stop his controversial experiments. The mission is thus completed successfully.

Post-mission, Mallika is seen with Shiva's family, indicating a personal resolution. Shiva’s responsibilities are not over, as he is shown heading to Afghanistan for another mission, highlighting his ongoing commitment to his duty.