Brutal kidnappings and murders of 8-year-old girls poses a tough challenge for the Warangal Police Department. After the investigating officer meets with an accident, Muhammad Khayyum is appointed. Can he solve the murders?

A young man recently released from prison teams up with his uncle to kidnap a wealthy girl, but things take an unexpected turn when her father launches his own investigation into the matter.

A handicapped man Krishna (Suriya) arrives at Mumbai from Kanyakumari at a train station after boarding a train from there. He, along with a taxi driver Raja (Soori), travel around Mumbai to look for his elder brother, Raju. Raja tries to get to know about Krishna but is unable to get any details about him from him. Krishna rents a hotel room, takes a shower, and changes his clothes. He gets Raja to take him to a club, where Krishna then tries to meet an old associate of Raju named Amar, who is a very powerful gangster through his henchmen, but fails. He then meets a close friend of Raju named Rajiv (Asif Basra), who overheard his conversation with Amar’s henchmen. Rajiv tells Krishna that Raju is Raju Bhai (Suriya), a powerful and feared gangster. He then tells things to Krishna about Raju, until he passes out from being drunk.

A series of murders happens in a City (Chennai), which is investigated by CBI Officer Evvi Ilavalavan (Natty Natraj). Will he find the answers for the question Who, How and Why of the crime, that too in time?

Archana (Sridevi) is a popular singer, and Johnny (Rajinikanth) is her ardent fan. Johnny is a conman who does petty thefts (only on the greedy ones) to close the loan taken by his father. He never misses Archana’s concerts, and she notices this. A tender love develops between the two, but Johnny is guarded in accepting Archana’s love due to his not-so-clean background. But one day Johnny accepts Archana’s love when she proposes to him. Meanwhile, Vidyasagar (Rajinikanth), a barber and lookalike of Johnny, lives a lonely life with his assortment of pet animals. He falls for Bhama (Deepa), another loner, and they both plan to marry. Vidyasagar notices his lover’s infidelity and kills her in rage. Knowing about his lookalike Johnny and knowing that he is wanted by the police, he tries to pass on the murder charge to him and gives up on women as well looking at them in low light.

Muthu, a low caste youngster, goes to the streets of Mumbai for a living. His quest takes him to a series of unexpected events, where he gets involved in the underground activities of Mumbai’s Tamil gangsters. Will he get to the top?

Narayanan (Namo Narayana) is the son of Central Minister Pandiyanar (G. Gnanasambandam). He makes money by corruption. One day, some goons try to kill a man in daylight. The man is lying in a pool of blood, and a local witnesses this and informs to the ambulance. The ambulance driver is Vishnu (Samuthirakani), a kindhearted man who has never let anyone he has taken in his ambulance die. Vishnu admits the man in the hospital, and he is saved. Narayanan is angry with Vishnu for saving his enemy, for which he replies that saving lives of people is his duty. Vishnu has a father (Vela Ramamoorthy) and sister Mahishasuramardini (Arthana Binu), who is stalked by Vicky (Vikranth), a drunkard and jobless youth who happens to be a friend of Vishnu. Vishnu convinces Vicky to make him attend the medical technician course. He completes it and saves people’s lives. Mahi has a friend who is stalked by Ravi, Narayanan’s brother, and she beats him in a bus.

The film begins with Professor Tiwari (Pankaj Kapur) being interviewed about police encounters and bids to eradicate organised crime from Lucknow and its surrounding areas. It then showcases Ajay Kumar (Arshad Warsi). Since he was young, Ajay has been traumatised by the death of his army officer father, who killed himself when accused of being a deserter, leaving his widow Prabha (Suhasini Mulay) to bring up Ajay on her own. Ajay studies hard and successfully becomes an Indian Police Service officer with the title of Senior Superintendent of Police of Lucknow. Due to his honesty, he gets transferred to various states in India, around 14 times in eight years. At his new posting in Uttar Pradesh, he comes to terms with a new criminal boss and ruthless killer, Gajraj Singh (Sushant Singh). Ajay engineers the setting up of a Special Task Force to deal with Gajraj. However, he also runs into problems as Gajraj is politically well-connected. Gajraj continues to elude the Task Force, using more modern technology such as the use of cell phones. But the Task Force recovers and is able to monitor Gajraj’s cell phones with the help of Prof. Tiwari. They find out that Gajraj is planning to contest the elections and if he wins, no police officer of any rank, even the Task Force, would then dare to arrest him or even consider him a suspect, which may well result in the Task Force being mere paper tigers. They have a final confrontation inside a train which leaves from Hazrat Nizamuddin railway station. All the officers in the Task Force as well as members of Gajraj’s gang kill each other in the fight, leaving Prof. Tiwari as the only witness.

Krishnaswamy (Kamal Haasan) is a widower living happily along with his mother-in-law Saraswathi (S. N. Lakshmi), daughter Kaveri (Mahanadi Shobana) and son Bharani (Mahanadhi Dinesh) in a village near Trichy. Dhanush (Cochin Haneefa), a con from the city, has an eye on Krishna’s prosperity and asks him to join his chit fund business. At first, Krishna is reluctant; however, when a rich friend from a foreign country visits his house, he too wants to be rich like them. Hence he agrees to Dhanush’s proposal and arrives at the city. However, he is unaware of Dhanush’s tricks and when Dhanush swindles away the chit fund money, the blame is put on Krishna, and he lands up in jail. He finds that even his future father-in-law Panjapakesan (Poornam Viswanathan) is also in jail for the same reason, whose daughter is Yamuna (Sukanya), working as a nurse. He advises Krishna not to be angry if the jailor is cruel, as he might be released sooner if he is submissive in the jail. During Krishna’s tenure in jail, Yamuna takes care of his family. Due to unavoidable situations, his mother-in-law dies and his children go missing. Krishna learns this after coming out from jail suffering unnecessary hardships.

Sanjay (Arjun Sarja), a fearless and upright police officer, is transferred to a new city. He lives with his widowed mother (Kavitha) and sister. He also has a half-brother Ashok (Nassar) and stepmother. Ashok works for the corrupted minister Sabapathy (Captain Raju), who is involved in liquor smuggling, procuring, and illegal gambling. One day, a corrupt police officer Sridhar (Sakthivel) tries to rape an innocent girl Anjali (Kushboo). Sanjay arrives on time, saves Anjali, and beats Sridhar. Sanjay later gets married to Anjali. He strongly supports the politician Sathyamoorthy (Charuhasan). Sabapathy decides to target Sanjay’s weak point: his wife Anjali. What transpires later forms the crux of the story.

JK, a CID officer, is forced to take up a case while on a lookout for his own sister who is missing. While investigating, he realises there is more to the case and goes on to unveil the mystery.

When a doctor gets jailed for a string of shocking murders, his loyal wife sets out to commit a copycat crime to prove his innocence.