His hunger for conquest not satiated, even after repeated victories, Maharaja (Great King) Ajatashatru (Sunil Dutt) of Magadha would like to continue on his winning spree, as the only unconquered city is that of Vaishali. His astrologers forewarn him; his Senapati (General) (Prem Nath) cautions him that his army is tired and needs to rest; his very own mother refuses to let take part in any war - but he refuses to listen to anyone and hastens to war - which leads to subsequent defeat at the hands of the Vaishali Army. Wounded, lost, and on the run from enemy soldiers, Ajatshatru dons the guise of a Vaishali soldier and takes shelter with a woman named Amrapali (Vyjayanthimala). She nurses him back to health but Amrapali doesn't know that he is the Ajatashatru of Magadh yet they fall in love with each other.
Ajatashatru finds an ally in Senapati Badbadhra Singh (K. N. Singh) and both start to plot against Vaishali - this time by reducing the number of soldiers, making them addicted to alcohol, poor training methods, and poor pay - thus demoralizing them, and paving the way for an easy victory for Magadha. Amrapali, winning a dance competition, is crowned the Rajnarthaki (Government Dancer) of Vaishali. She is known to everyone as a true patriot. One day, she finds out that the soldier she loves is none other than Ajatashatru. Being a true patriot, she breaks all ties with him and tells him to never see her again. Heartbroken, she tells the ruler of Vaishali that she would like to leave the position of Rajnarthaki. The members of the court put pressure on her and everyone finds out that she had fallen in love with Ajatashatru and declare her as a traitor.
The ruler of Vaishali sentences her to life in a dungeon with orders to execute her on a full moon night. Ajatshatru, who is enraged to hear this, gathers his army, and storms the unsuspecting people of Vaishali and virtually burns the city down, killing almost everyone in it. He then rushes to free his beloved from the dungeons. He does set her free - but it is not the same Amrapali - this Amrapali is quite different and not at all thrilled to be in the presence of her conqueror lover. She is taken by him to the battlefield and is shown everyone he killed just to get her. She is horrified to see so much bloodshed. She tells she can't live like this anymore and surrenders herself to Gautama Buddha (Narendra Nath). Ajatashatru also follows her and surrenders himself.