Ramachandran (Sachin Khedekar) is a genetic scientist who does not get due credit and funds for his research. He tries creating a human with several talents through baby designing, which thus leads to the birth of his sons, who are conjoined together above the waist. Since they share a common heart, doctors suggest a sacrificial surgery, to which their mother Sudha (Tara) objects. They begin raising their children, Vimalan and Akhilan (both played by Suriya). In the following years, Ramachandran makes it big with the help of Sudha. His company, Locus Lacto Products, makes huge profit through their product “Energion”, the top-selling children’s powdered milk energy drink in the market.
Vimalan and Akhilan are poles apart in character, the former being decent, intellectual and good at studies while the latter is happy-go-lucky, socialising and poor at studies. Anjali (Kajal Aggarwal) joins their company as a translator. Both Vimalan and Akhilan are smitten by her. She, along with her Russian friend Volga, a journalist, spend their time with the brothers. Meanwhile, Anjali falls for Vimalan and Akhilan is jealous, yet feels happy for them. Volga is then revealed to be a spy who seemingly tries to steal the trade secrets of Energion. She is exposed and sent out by Ramachandran. She then takes the brothers to their cattle farm under the pretext of an interview where she takes pictures and even collects a milk sample from their farm. When Vimalan questions her, she warns him that Energion is an adulterated product and can lead to the death of thousands of children. She also exposes their father of killing the head of their R & D department and setting the lab on fire, thereby destroying evidence. Consequently, she is murdered, but, she swallows a pen-drive containing evidences of the foul-play before dying. Anjali acquires it from the person who performs Volga’s autopsy. She hands the pen-drive over to Vimalan. Following this, Vimalan and Akhilan are confronted by goons who try to get the pen-drive from him. Akhilan is convinced that the attack was only meant for robbing them. During this fight, Vimalan suffers a huge blow on the head.