It tells the story of a pilot Sundar (Raj Kapoor), who upon returning home from war after being assumed dead, weds the woman Radha (Vyjayanthimala) he had long loved, unaware that she had been planning to marry his best friend Gopal (Rajendra Kumar).

[3] Sangam released on 26 June 1964 to widespread critical acclaim, with high praise for its novel concept, direction, screenplay, dialogue, soundtrack, costumes, cinematography and performances of the cast, and was widely considered as Hindi cinema's greatest love triangle.

[6] Sangam is widely regarded as R. K. Films’ magnum opus and the career-best performances of Raj Kapoor, Vyjayanthimala and Rajendra Kumar.

Eventually, Sundar enlists in the Indian Air Force and is assigned a dangerous mission in Kashmir, delivering items to soldiers fighting there.

The self-effacing Gopal sacrifices his love once more, stepping back into the shadows and watching as the reborn Sundar resumes his wooing of Radha.

Radha is resolved to be faithful to her husband and to put Gopal out of her mind, privately asking him to stay away from her and Sundar because of the torture his presence causes her.

The perfection of their marital bliss is, however, shattered when Sundar accidentally discovers the unsigned love letter Gopal had written to Radha.

An enraged Sundar pulls a pistol on his wife and demands she divulge the name of her supposed lover, threatening to kill the man, but she refuses.

Radha's life becomes miserable, lived out against the incessant drama of Sundar's jealousy, threats, anger, and fixation with the letter.

In the late 1940s, Raj Kapoor planned to launch a film under the title of Gharonda with Dilip Kumar, Nargis and himself in the lead playing the central characters.

Lead actress Vyjayantimala made her debut as a singer by beautifully humming to the tunes of "Yeh Mera Prem Patra", along with Mohammed Rafi.

[12] Furthermore, Sangam also ranked as the second highest-grossing film of the decade by Box Office India behind Mughal-e-Azam (1960), where its adjusted to inflation net reportedly was about ₹885,700,000 (US$10 million).