The film starts with Tamil (Vimal) who is raised single-handedly by his grandfather, Venkatasamy(Raj Kiran) in a village, as his parents had committed suicide after eloping and giving birth to him. 25 years later the boy is working in a Chennai-based IT company, staying in an modern upmarket apartment. Tamil meets Karthika (Lakshmi Menon) a medical student using tricks to get to the front of the traffic signal. They fall in love at first sight, and end up being so engrossed in each other that they don't realise that the signal had gone green. The way Karthika tricks the police officer and gets away with it endears Tamil to Karthika. He follows her and in no time she reciprocates.
Set against the backdrop of most happening the Koyambedu market, the film revolves around the lives of four young boys played by Kishore, Sree Raam, Pandi and Murugesh. They work as coolies, and earn their bread by working as lifters. They lift and transport vegetable stocks to various shops. One such shop is owned by Aachi, who treats the boys like her sons. The boys are carefree and do not worry about their future, and have fun by teasing and looking at schoolgirls who pass by. They befriend a girl named ATM, who assists them in finding a new friend, who turns out to be Aachi's daughter. They all become friends and hang out together. One day Aachi tells the boys that, they do not have an identity and how long will they live like this? She advices them to do something that will give them an identity and let them earn some respect. They decide to start a mess in the market, where so many people will have access. Aachi helps them to get an old godown from Naidu, a rich Dada, who controls the market. Naidu lets them have the place for free for now, and says will collect the rent later. The boys start the mess and it becomes an instant hit, earning them money and respect. The boys feel that they have now got an identity as the owners of Aachi mess.
The protagonist in the film, Gandhi Babu (Natraj) is a skilled conman. He dreams up ingenious scams and executes them perfectly. He sells ignorant people ordinary snakes claiming that they are exotic and will fetch crores in the international market. He promotes a non-existent 'multi-level marketing' company with its controversial chain referral schemes promising a BMW car within the year. And the climax has him pulling off 'the rice pulling scam', one of the most high-profile scams of recent times. About 40 minutes into the film Gandhi Babu is arrested and multiple cases filed against him. But the money he has scammed over the years comes to his rescue and he is released. He is not in the least remorseful and continues to manipulate everyone. He believes that if a person is foolish or greedy enough to be duped, then the person is to be blamed. He argues that every election voters are conned by the candidates who promise them the moon, but never come through. Banu (Ishara Nair) is from a poor family. She comes to work for him and falls for his charms. Despite having a soft corner for her, money is Gandhi Babu's first priority and he abandons her. Some of his friends betray him and is beaten to pulp. Banu looks after him for some time and they get married. She becomes pregnant. Towards the end of the film, a group of people whom he had tricked, capture him. They threaten him to settle their lump sum of money. He performs a final heist to hand over the money to them. The passage of money results in a tussle. Babu kills each one of them and returns to his wife and child with the money. Finally, the look on her face makes him realise the value of life and leaves the money to the police custody.
Bergmans (Arjun), a brilliant but unruly student, is thrown out of his seminary for committing the sin of the flesh after being caught red-handed by fellow student Sam Fernando (Arvind Swamy). Blaming the good-hearted Sam for his ouster, Bergmans vows revenge and challenges to prove that evil does reign supreme in this world. Sam finishes his education and training and arrives at a village as the new Father of the local church. A local boy named Thomas of this village who is the illegitimate son of a local fisherman (Ponvannan) has grown up in a rough neighbourhood, following the death of his mother and thus being forced to fend for himself.
Shiva (Karthi) is a young, carefree, unemployed man staying in Bangalore. He has a loyal group of friends including his best friend, a young woman named Priya (Sonia Deepti) with whom he shares his feelings. His friends are determined to get him a job. One day he sees a young, beautiful woman named Charulatha (Tamannaah), who is also looking for a job. Shiva is immediately attracted to her. He subsequently spots Charulatha on various occasions and follows her, but loses sight of her each time. He even misses a job interview Priya has arranged for him.