Karan Shergill (Hrithik Roshan) is a young man who has no goal or plans for his future. His father is a businessman, his brother is a successful individual living in America. His girlfriend, Romi (Preity Zinta), a student activist and reporter who espouses fashionable causes out of well-meaning sincerity, tells him he needs to find a goal in life. When a friend announces he is going to join the Indian Military Academy (IMA), Karan applies as well, despite dissent from his parents.
To his surprise, Karan gets selected (though his friend backs out). But he is undisciplined and unused to the life there and keeps getting into trouble. Upset, he runs away from the academy, which causes Romi to break up with him. Karan finally comes to terms with his situation and makes his decision. He returns to the IMA, takes his punishment, and becomes a focused, disciplined cadet leader, graduating as an officer Lieutenant Karan Shergill.
Karan is posted to the 3rd Battalion of the Punjab Regiment, commanded by Col. Sunil Damle (Amitabh Bachchan) in the Kargil sector, and handles his responsibilities well. Karan comes home on leave and finds out that Romi is getting engaged; he goes to the ceremony to congratulate her. Karan is recalled to his post as his leave is cut short due to outbreak of hostilities in Kargil.
He reports back to his post where he is promoted to the rank of Acting Captain. His battalion CO briefs the officers on the latest situation. The battalion has been assigned to secure Point 5179, a crucial vantage point dominating the army's main supply line, the NH1D. The first part of the assault is successful. The battalion destroys the enemy's screening units with Karan cited for his bravery in saving another officer's life. Meanwhile, Romi gets stationed as war correspondent, where she meets a metamorphosized Karan.
Karan learns that Romi broke off her engagement. She tries to renew her relationship with him amidst the war, but this time Karan declines her. In the second phase of the assault Karan's unit engages in a failed attempt to storm and capture the Pakistani strongholds on the mountain. The Pakistanis have the advantage due to their strategic position and deal the unit heavy losses during the attack. Capt. Shergill and a group of 12 are next given orders to encircle the enemy position and attack it from behind. To do this, they must scale a 1000-foot rock wall. Karan realizes that he has finally found his lakshya (goal) in the form of the wall.
After the unit sustains an attack in a grass field and loses their commanding officer, the remaining men scale the cliff and attack the Pakistani stronghold during the night. The movie ends with Col. Damle looking out across the mountains the next morning, to see an injured Capt. Karan hoisting the Indian flag atop the ruins of the stronghold. Karan's father, who was skeptical and disapproving of him, is now proud of his son. Karan is given a leave following his condition, whereupon he and Romi reunite.