The story is about Azhagu Sundaram (Dhanush) a village bumpkin who comes to Chennai city from Tirunelveli to earn money to buy gold bangles for his mother! He gets entangled in the big bad world of dons and goondas and is unable to get back home too see his beloved mom. On the other hand, Meenakshi (Archana) the loving mother lands up in Chennai in search of her son without even knowing his address or whereabouts. Meenakshi bumps into Shwetha (Meera Jasmine) a journalism student who takes pity on the old lady, takes her home and promises to help her find her son. Azhagu is now known as Parattai, in Chennai and is taken under the wings of Bhai (Nassar) a tea shop owner. Parattai is forced to take the aruvaal as gang wars erupts and single handedly he wipes out Deva, Kesavan and Suri (Aditya, Katha Dandapani, Aryan) all dreaded criminals in the city. On parallel lines he never sees his mother and finally accompanies her dead body to the crematorium thinking that it is an orphan's corpse! He dances with others, offers flowers and finally after her body is charred, he realizes that it was his dear mother!