Aegan (Protector) is a Tamil action and romantic movie directed and co-written by Raju Sundaram and produced by Ayngaran International. Ajith Kumar, Nayantara and Suman in the lead roles. Jayaram, Navdeep and Piaa Bajpai, prominent actors from the south Indian film industry, played other pivotal roles in the movie.

Ekan revolves around a dare devil cop who, on behalf of his ailing father and the ambition of a lieutanent general returns to college in Ooty. Whilst protecting the general's daughter, he attempts to reconcile with his step-brother from his father's illegitimate relationship. Furthermore, he has to ward off the international criminal John Chinnappa, who is trying to kill the genral, an ex-aide of his who has turned police approver. How the cop manages to solve all three problems forms the crux of the story.

Egan's story is based around the mission Shiva (Ajith Kumar), a CBI officer and his efforts to foil the terrorist John Chinnappa (Suman). Major Shiva is simultaneously attempting to mend relations with his father's estranged first wife and his half-brother Narain; complications ensue.

Major John Chinnappa is a former military officer decommissioned and court martialed for executing eleven Pakistani civilians who accidentally crossed the border looking for water. He wants to sabotage a military project called Milaap (Unity), a first step towards friendship between India and Pakistan. India will release fifty Pakistanis imprisoned for crossing the border into India which most of them are illiterate villagers who wandered over the border by mistake. Chinnappa does not want the state of war between India and Pakistan to end and believes that Pakistan will betray India in the process. He lost his son in the Indo-Pak wars in Kashmir and cherishes an abiding hatred for Pakistan and all Pakistanis.

First he tries to stop Project Milaap by killing the general in charge, General Ram Prasad Bakshi (Devan), the commander and chief of the Indian Army, during a national television interview with him taking many hostages. This fails due to Major Shiva's intervention though Chinnappa does succeed in killing Brigadier Karthikeyan (Nassar), Major Shiva's father, who had ordered his decommission.

He also shoots the talk show host in the shoulder for interrupting his flow of questions for the General and also threatens his daughter Pooja (Piaa Bajpai). As Karthik dies, he tells Shiva about his step mother Madhu (Suhasini Mani Ratnam) and step brother Narain (Navdeep) and begs Shiva to re-establish relations with them, who are to be found at St. John’s College in Tamil Nadu called Ooty. Both brothers should cast their father's ashes into the Ganges river.

The General later asks Major Shiva to go undercover as a student at the college to protect Sanjana since she will escape from anyone who is a military uniform. Ram pleads that he has never seen a civilian college before and doesn't know much about the current generation. The General points out that, by a strange coincidence, Pooja attends school in the same town where Narain lives, so Shiva can protect Pooja and look for Narain at the same time. Shiva goes undercover as a student returning to college after many years away taking care of the family business to complete his education. He is much older than the other students, who at first make fun of him because of his lack of new-generation styles. He also has to deal with the many goofy teachers as well the idiotic forgetful principal of the college, Albert (Jayaram), as well.

He finds Narain who is somewhat of a legend and idol at the school having failed the exams three times and who is later revealed to be Shiva's brother. Pooja is Narain's best friend and his secretly jealous that other girls can get his attention but she can't. Shiva shocks everyone with his effort to save Narain from falling down with his military training. He later becomes a sensation among the students and teachers and also befriending Narain and Pooja and falls in love with the chemistry teacher Mallika (Nayantara) after the students dare him to sing for anyone new coming in through the college's main entrance.

Meanwhile Chinnappa gives an order to shoot a friend of Narain and Pooja, shocking many of his comrades in order to show that if he can kill one of her friends, he can definitely kill her as well. Shiva and his friends go to the movies until he spots a SUV and the student. Shocked, Ram quickly intervenes causing Chinnappa's right-hand man Khan (Sriman) to fail killing him with a sniper rifle. Shiva then chases them down and captures Khan, whom he tortures to get information about Chinnappa and his operations on stopping Project Milaap. Ram also convinces Pooja to talk to her father and also helps her on getting Narain's attention, which she later feels as cheating him.

Chinnappa is frustrated with Major Shiva's actions and decides to go undercover as a teacher at the college. When the prom comes and after everyone dances, Mallika is kidnapped by Chinnappa's men right before Shiva's eyes who later chases them and kills them, the last one holding her hostage by shooting him in the leg through Chandani's sari and then finishing him off. Later Chinnappa tells Narain's family about Ram being his step brother learning it from the idiotic principal of the college.

Narain and his mother have always suffered due to the fact that their dad had refused to abandon Shiva after Shiva's mother died even if it meant losing Narain. Narain had previously expressed his hatred for the army and his son not knowing it is Shiva, hurting Shiva's feelings. Shiva later tells them that he came to them to complete his father's last wish to reunite the family showing them his ashes in the pot and leaving them in grief after hearing about his death.

Chinnappa later takes the entire school hostage and asks for Khan to be released, Major Shiva in handcuffs brought to him by a helicopter, and Project Milaap to be stopped or everyone will be executed. When General Ram Prasad tries to stop Project Milaap, Shiva stops him saying that taking this opportunity away will mean another many years of hatred between India and Pakistan, especially since Pakistan agreed to free fifty Indian prisoners in return. There he arrives in a hall where all the frightened and worried students and teachers are being held along with Naraian and Pooja.

Khan has been convinced by Shiva that Chinnappa is wrong and helps Shiva fake his own death horrifying the students and shocking Chinnappa who doesn't want Shiva to die yet. Shiva then proceeds to kill the rest of the terrorists keeping the students within the hall and sets them free. Chinnappa is shocked and tells his comrades to search for the students and kills Khan for betraying him after he tells him that he has lied about his mission of making India a better country.

Meanwhile General Ram Prasad meets with a Pakistani army general at the border who congratulates him on the success of the project and the now releasing of the prisoners. Chinnappa finds Shiva and battles Shiva in a deserted part of the school. Narain on the other hand gets onto an army helicopter to rescue Shiva. After the fight, Chinnappa has a gun being pointed at Shiva and threatens him to turn around and look at his death before his eyes.

Shiva turns around and tells him that it is a shame that he always forgets how a story ends with the bad guy always dying at the end by showing him a pin he had pulled of one of his hand grenades secretly. As he runs towards the chopper,Chinnappa closes his eyes and dies in the fiery explosion which also sets off the explosives planted underneath the roof. Ram jumps off just in time when the entire roof has gone up in flames. On the border, Pakistani and Indian prisoners are released and returned to their longing families and Shiva and Narain empty their father's ashes into the Ganges river.