Stain is a romantic action based movie, in which Chiranjeevi and Trisha played the main lead roles along with Prakash Raj in negative role. Actress Anushka Shetty doing an item number in this movie. A. R. Murugadoss directing this movie under Nagendra Babu's production banner Anjana Productions. Mani Sharma scored music.
Stalin (Chiranjeevi) is a Major in the Indian Army. He returns to the society as the Colonel (Mukesh Rishi) transfers him to administrative division from the battlefield in the name of disciplinary action. After returning from the Army, he stays with his mother (Sharada Urvashi). Stalin keeps helping a physically challenged girl Sumati to write her Intermediate examination and her suicide disturbs him.
The death occurs as none of the people around her extend help. Then Stalin plans a chain system. The theme works on a principle that everyone should help others and in return they should not seek a mere thanks but tell those who get the help to help three more, with a condition that those who get help from them should also demand the same. Stalin thinks that this chain will develop helping attitude among the people. But, to his dismay, Stalin finds that the chain did not work.
On one occasion, Stalin bashes a rich boy, Chris Mogni who injured a beggar. This goes in chain reaction and the rich boy employs some goons to attack Stalin. As Stalin disappears from the scene, the goons take Stalin's sister (Khushboo) and friend Chitra (Trisha Krishnan) into their custody. Stalin reaches the spot and hacks the hand of one goon. That goon happens to be the henchman of an MLA (Pradeep Rawat) who is also the son-in-law of Home Minister Muddu Krishnayya (Prakash Raj).
The Home Minister takes it as a prestige issue and tries to eliminate Stalin but loses his son (Riaz Khan) in the process. When the Chief Minister intervenes to bring in a patch-up, the crooked Muddukrishnayya plans to kill him and implicate Stalin in the murder. But Stalin takes away the injured Paul Matteo and saves him.But, Stalin gets a severe chest pain due to exertion. The reason for the chest pain is a bullet, which remained in his chest, very near to the heart.
Stalin sustains the bullet injury in the Kargil war and that was why the Colonel shifts him to administrative department. Finally the truth prevails and the Chief Minister returns to the hospital to visit Stalin, that the help three people concept was his brainchild, which saved him from death in the form of a school girl. Finally, the doctors successfully remove the bullet, in a very delicate surgery.
Stalin comes to know that his "help three people" concept worked well and the same theme saved his life in the form of auto driver. He thanks all the people for making his concept a success.