The story of Asoka goes back to about 260 BC, in the Empire of Magadha in India. Prince Asoka (Shah Rukh Khan) survives the many plots of betrayal planned by his brothers, led by the evil Susima (Ajit Kumar), who even desires to take his life, contemplating to inherit the throne of the Magadha Empire. For his safety, Asoka is ordered to leave Magadha by his mother and it is during his travels in this period that he encounters Princess Kaurwaki (Kareena Kapoor) and her brother, Prince Aryan (Sooraj Balaji) from Kalinga, who are undercover and protected by General Bheema (Rahul Dev).
Just when Asoka and Kaurwaki fall deeply in love with each other, Asoka’s mother calls him back to Magadha. On his return, he finds Kaurwaki who was attacked by traitors of Kalinga, missing. Soon after, Asoka's mother is killed by one of Susana's men. This infuriates Asoka, who proceeds to kill all his evil brothers except Sugatra, who escapes to Kalinga. Asoka decides to conquer Kalinga. However, after the war is over he realizes that he has not conquered an empire, but has only brought about death and destruction. It is the war of Kalinga that brings a complete transformation in him, as he goes on to embrace Buddhism and spread its virtues and the peace, love and kindness that it preaches amongst his people.