An orphan boy begins working in the house of a wealthy man named Ramnath (Shreeram Lagoo). Ramnath does not like him. It is later revealed that another orphan had killed his wife, hence his animosity. Ramnath's young daughter Kaamna, however, empathizes with the boy and they form a friendship. Eventually, the boy is adopted by a Muslim woman named Fatima (Nirupa Roy) who also works for Ramnath, and who names him Sikandar (meaning: Conqueror.) On the occasion of Kaamna's birthday, Sikandar is refused entry to the party, and when he breaks into Kaamna's room to deliver her gift he is caught and accused of trying to rob the house. He and his mother are banished from Ramnath's home. Shortly thereafter, Fatima dies, leaving young Sikandar with the responsibility of looking after her daughter, Mehroo. A fakir, Darvesh Baba (Kader Khan) advises the mourning Sikandar to embrace the woes of life and find happiness in sadness, for then he would become the conqueror of fate.

The film cuts to grown up Sikandar (Amitabh Bachchan), revealing he has amassed a fortune by turning in smugglers and thieves to the police and receiving the reward payouts. With all his wealth, he has managed to build an impressive house for himself and Mehroo, along with setting up a profitable business. He still has not forgotten Kaamna (Raakhee). She and her father have fallen on hard times, but they snub all offers from Sikandar to become reacquainted. When Sikandar tries to speak to Kaamna she demands that he never speak to her again. Sikandar is upset by this and becomes a heavy drinker. He also begins to visit Zohra Begum's (Rekha) kotha (brothel) on a regular basis. Zohra falls into an unrequited love with Sikander and begins to refuse other clients.

One night in a bar, Sikandar is introduced to Vishal Anand (Vinod Khanna), a down-on-his-luck lawyer. A friendship is formed when Vishal risks his own life to save Sikandar from a bomb blast. Vishal and his mother move into Sikandar's house.

A criminal named Dilawar (Amjad Khan) is in love with Zohra, and learns about her love for Sikandar. Dilawar confronts Sikandar and in the ensuing fight is thrashed by him. He swears to kill Sikandar.

At length Ramnath and Kaamna, who have been struggling financially, discover that Sikandar has been anonymously paying their bills. Ramnath goes to thank him. The two households become friendly, and Vishal begins to work with Ramnath. Encouraged, Sikandar tries to profess his love to Kaamna through a love letter. Because Sikandar himself is illiterate, Vishal transcribes the letter for him, but the plan backfires when Kaamna mistakes the letter as actually being from Vishal. Vishal is unaware that Kaamna is the girl Sikandar loves, and they begin to date. Sikandar, upon learning this, struggles with his emotions but decides he must sacrifice his love for the sake of his friendship with Vishal. He covers up any evidence of his feelings toward Kaamna, and at his urging, Vishal and Kaamna plan to marry.

Meanwhile, the marriage of Mehroo is at risk of being cancelled; her fiancé's family have learned about Sikandar's frequent visits to Zohra, and they object to the union on these grounds. Vishal, knowing Sikandar won't change, visits Zohra and offers to pay her if she agrees to abandon Sikandar. Zohra, upon learning the reason, refuses the money but promises Vishal that she would rather die than let Sikandar visit her again. Later, Sikandar arrives at Zohra's. When she is unable to stop his entry, she kills herself by consuming poison hidden in her diamond ring, and dies in his arms.

Dilawar in the meantime has formed an alliance with Sikandar's arch enemy, J. D. (Ranjeet), and upon learning of Zohra's death hatches a plan to destroy Sikandar and his family. Kaamna and Mehroo are both preparing for their weddings; J. D. and his henchmen kidnap Mehroo but Vishal follows them and rescues her. Dilawar kidnaps Kaamna, but Sikandar follows him. He rescues Kaamna and sends her home while he fights Dilawar. In the final battle, both Dilawar and Sikandar are mortally wounded and Dilawar is surprised to learn that Sikandar never loved Zohra. A dying Sikandar reaches the wedding of Kaamna and Vishal. Just as the wedding ceremony is completed, Sikandar collapses. His dying words inadvertently reveal his love for Kaamna, and Vishal sings him a reprise from the movie's theme song: "Life is going to betray you someday... Death is your true love as it will take you along..." Sikandar's entire life flashes before him and he dies in Vishal's arms just as the song is completed. The film ends with the wedding having become a funeral.

• Amitabh Bachchan as Sikandar
• Vinod Khanna as Vishal Anand
• Raakhee as Kaamna
• Rekha as Zohra Begum
• Amjad Khan as Dilawar
• Ranjeet as J. D.
• Mayur Raj Verma as young Sikander
• Shreeram Lagoo as Ramnath
• Goga Kapoor as Goga
• Nirupa Roy as Fatima
• Ram Sethi as Pyarelal 'Awara'
• Kader Khan as Darvesh Baba
• Manmohan Krishna as piano instructor
• Paidi Jairaj as Dr. Kapoor
• Yusuf Khan as Seth Paul
• Vikas Anand as police inspector
• Sulochana Latkar as Vishal's mother

The Soundtrack was composed by the duo of the brothers Kalyanji Anandji, with the lyrics by Anjaan and Prakash Mehra (Salaam-e-Ishq).

Beside Kishore Kumar and Mahendra Kapoor, Mohd. Rafi's voice was used in the movie for the Kishore Kumar song Rote Hue Ate Hain Sab. Mohd. Rafi wanted Kishore Kumar to sing the sad version, but as insisted by Music Director Kalyanji Anandji, that his voice suited the sad version best, Mohd. Rafi had agreed to sing the song Zindagi to Bewafaa Hai. The song was picturised on Vinod Khanna during the Amitabh death scene.

Made on a budget of ?10 million (US$150,000), the film grossed over ?170 million (US$2.5 million) in India, the film was the highest-grossing film of the year and the third highest-grossing film of the decade after Sholay (1975) and Bobby (1973). Boxofficeindia.com declared the film a blockbuster.^[5]

Filmfare Awards

• Filmfare Award for Best Film
• Best Director - Prakash Mehra
• Best Actor - Amitabh Bachchan
• Best Supporting Actor - Vinod Khanna
• Best Supporting Actress - Rekha
• Best Comedian - Ram Sethi
• Best Story - Laxmikant Sharma
• Best Male Playback Singer - Kishore Kumar - "O Saathi Re"
• Best Female Playback Singer - Asha Bhosle - "O Saathi Re"