Jai Agnihotri (Salman Khan) is an ex-army officer whose passions include helping citizens and fighting criminals. He was a major in the Indian Army, but was suspended because he ignored orders from his superiors so that he could rescue a group of children from terrorists. After this incident, Jai moved in with his mother and sister Geeta (Tabu).
One day, Jai is unable to help a physically disabled girl, Suman (Genelia D'Souza), take an examination while her brother Rohan (Vikas Bhalla) is stuck in a traffic block. Suman became depressed because no one came to help her, and she commits suicide. Jai is greatly disturbed by this incident. With Suman’s death fresh in his mind, Jai created a system that would encourage citizens to help each other. Each day, citizens were to help three people. These three people would in turn help three more people, and so on. Jai believed that this network would foster kindness and a sense of community among the citizens. His system, however, faced challenges.
On one occasion, for one of his daily good deeds, Jai beat a rich man who had injured a child beggar. In an act of revenge, the rich man employed some men to take Jai's sister Geeta and friend Rinky into their custody. Jai was able to save his sister and friend, but in the process he injured one of the captors. This captor happened to be the henchman of a member of the Legislative Assembly, named Patil. Patil was the son-in-law of the Home Minister Dashrat Singh.
The Home Minister was not pleased that Jai had injured one of his sons-in-law’s henchmen. He attempted to avenge this injury by kidnapping Jai’s nephew. The Home Minister lost his son-in-law in the process. The Chief Minister, Ashok Pradhan, meanwhile found out about Jai's system after his own life was saved by a schoolgirl performing her good deeds for the day. The Chief Minister decided to intervene in the dispute between the Home Minister and Jai in an attempt to put an end to their fight. The Home Minister did not appreciate this intervention. He planned to kill the Chief Minister and frame Jai. Jai, however, was able to save the Chief Minister.
The Home Minister’s son, Arjun Singh, and his hired men attack Jai. Jai killed Arjun, but not before he was severely injured after getting stabbed by the Home Minister’s daughter, Kavita Singh Patil. A rickshaw driver and a former colleague, Arjun Kaul, together helped Jai get to the hospital. While Jai was at the hospital, the Home Minister spread rumors that Jai was responsible for trying to kill the Chief Minister. Once the Chief Minister recovered, he revealed that it was the Home Minister, not Jai, behind the attempted murder. A crowd beat the Home Minister after hearing the truth.
Doctors were able to save Jai. Jai had survived thanks to his own help-three-people concept. When Jai emerged from the hospital, he found thousands of people waiting for him. Jai thanked them all for making his concept a success.