Bio-scientist Govindarajan Ramaswamy speaks at the Jawaharlal Nehru Stadium about chaos theory and the butterfly effect. He begins by reciting events from the 12th century in Chidambaram, when King Kulothunga Chola II, a Saivite, persecutes Vaishnavites and intends to destroy an idol of Govindaraja. Rangarajan Nambi, a Vaishnavite, protects it and offends the king, who orders Rangarajan to be executed by being pierced, stoned, submerged into the sea with the idol, before being devoured by the shark, thus the king succeeding.
On 20 December 2004, a nano bio-technology lab in the United States designs a vector-virus intended as a bio-weapon. When they were watching the insound of his lab monkey breaking out of his cage and retrieving a sample of the test virus. The monkey, who thinks the vial as the usual chocolate Govind would feed him, swallows the sample of the virus. Govind and his co-workers watch helplessly as monkey dies. Govind, saddened by the event, quarantines the lab room by filling it with concentrated salt solution, the only antidote to the virus. After understanding the original virus’s lethal potential the hard way, Govind refuses to hand over the main single vial containing the virus, due to fear of misuse. However, his boss, Dr. Sethu, has a malicious plan in mind, and tries to sell it to a terrorist group. Govind tries to sneak the vial out of the lab in order to save the vial from Sethu’s evil plan, but is pursued by the security guard and the police. Govind flees to his friend and coworker Suresh’s house for refuge, who secretly betrays him.

Agent Wali Khan (Irrfan Khan), appointed by the Chief of Indian intelligence agency Research and Analysis Wing (RAW), Ashwini Rao (Nassar), has been on a mission for nine years to keep an eye out for the activities of India’s most wanted D-Company leader, Goldman (Rishi Kapoor) while working as a local barber as a cover. One day he notices Goldman talking about his son’s wedding cards to people in the mosque where he prays and comes to know that his son is getting married and Goldman is breaking his security protocol to attend that. The same is confirmed by an ISI operative who works part-time as Goldman’s bodyguard and is a neighbor and friend of Wali though he doesn’t know the truth about Wali’s connections to Indian Intelligence. Sensing a chance to nab Goldman alive, he informs Ashwini about the same who assembles a team quickly – Ex-Indian Army officer and mercenary, Rudra Pratap Singh (Arjun Rampal), RAW’s explosives expert, Zoya Rehman (Huma Qureshi), and Aslam, a Mumbai thief and a murderer who was given a chance at freedom by participating in this mission.

The film revolves around a maneater tiger who has gone berzerk and is no attacking people in Iduppanai, Kotagiri. While the forest officials are searching for the tiger, strange events happen in the forest.

The Film is about transformation of a Hero (Satyaraj) who has a prison record and his understanding of Love through an elementary education. In that process he falls in love with the school teacher Heroine (Rekha).
Based in a coastal sea village, Chinnappa Das (Satyaraj) is a violent person who has prison records and returns to his village after serving his prison term. He is persuaded by his Maternal uncle’s daughter (Ranjini) to marry him. In one of his encounters at an elementary school he meets a lady school teacher Jennifer (Rekha) who gives a sound scolding on how ignorant fools behave.

The protagonist`s family wants him to continue his family legacy by becoming a policeman. The journey, however, is not going to be easy since he has a minor defect in his body, Will he let this obstacle stop him from pursuing his parents` dream or will he overcome it to come out on top, This struggle forms the core content of the movie.

Raja who is born blind but has extraordinary senses and is a trained skillful fighter is assigned to rescue a girl.

The film begins with Gaythri (Sneha) getting married to an irrigation engineer (Vikramaditya) against her wishes. As she conducts her marriage with mechanical unconsciousness, her sunken heart reflects her past. Gayathri, a marine student, goes to Rameswaram to study coral reefs and marine ecosystems while staying with her uncle (Vinu Chakravarthy) in a fisherman hamlet. She witnesses Chinna (Arjun) and his assistants (Mansoor Ali Khan and Ponnambalam) – local mobsters working for a gang – committing pitiless and violent crimes. Though she wanted to report these crimes to the local SP (Vijayakumar), her uncle dissuades her. Meanwhile, she asks her uncle for a guide to take her to locations rich in marine life. Her uncle directs Chinna to help Gayathri in her pursuit. After a couple of close encounters with Chinna, Gayathri understands his soft nature and vows to reform him as a socially acceptable man. Later, love blossoms between them. Even as Chinna tries to make his life straight, a violent feud ensues between him and the local gang. Trying to save Gayathri, Chinna kills the gang leader and is sentenced to life imprisonment. Taking advantage of Chinna’s absence, Gayathri’s parents marry her to the irrigation engineer. As the story ploughs through in the second half, Chinna, characterized by the obsession with “Gayathri”, kills people working against his goal to attain his ladylove. At the end, after much drama, when Chinna almost killed Gayathri’s husband, she shot him in order to save her husband. Chinna asked her if she had feelings for him before this, at least for a second. Just after she shook her head saying yes, he jumped off the building. The movie ends there indicating his death.

Ravi Teja plays a young man desperate to become a police officer. He winds up getting embroiled in a plot to pose as his lookalike in order to re-capture an infamous criminal from rogue cops.

Raghavan (Sarathkumar) and Velu (Vadivelu) work as cooks in a non-veg hotel. Raghavan loves Geetha (Kiran) who is the daughter of a rich man (Vijayan), but her father is against this love and insults him as a poor man. Raghavan challenges that he will be rich in a year. There is a subplot in the story, for Meenakshi (Sharmili), a daughter from a rich family; she is the apple of the eye of the family. Meenakshi ran home with her lover Raju, who worked as a driver to her house. He tells that his friend Dinesh will help them. However, Raju escaped because he saw a bad dream where he is killed by her family as if it will happen in reality. Due to that he vanishes. Raghavan understood her plight and helps her.

Shivshankar, a person who uses a wheelchair, tries to make his son, Vishnu, aware of his responsibilities but to no avail. Things take a turn for the worse after Vishnu tries to rape a girl.

Singapore-based Dr. Siddhant Arya recruits a superhumanly powerful Indian-born man named Rohit Mehra, who was given special powers by a blue-skinned alien named Jadoo, to build a computer that can forecast the future, which results in an accident that kills Rohit. When this news reaches Rohit’s mother, Sonia, in India, she passes this on to Rohit’s wife, Nisha, who has just given birth to a son named Krishna. However, Nisha, unable to handle this devastating news, passes away, leaving Krishna to be brought up by Sonia. When Krishna is enrolled in school, she notices that he has the same intellectual and physical powers that his father possessed, so in order to shield him from any harm, she moves to a secluded and remote area in a mountainous region of the country, where he grows up. Years later, Krishna has matured, has acquired the same special powers that his father had, and is also able to communicate with animals. He meets with a camper named Priya and is attracted to her.

Raghu and shanti are divorced couple which sparks problems between Suriya(shanti’s brother) and Vijay(Raghu’s brother).