In early 1900s Bengal, Devdas Mukherjee returns from law school in London after ten years, rekindling a childhood bond with his neighbour Parvati, known as Paro. Their friendship blossoms into love, but Devdas's aristocratic mother, Kausalya, rejects Paro due to her lineage tied to nautch performers. A public proposal by Paro's mother, Sumitra, leads to insult and humiliation. Heartbroken, Paro is married off to a wealthy, much older widower. Unable to confront his family, Devdas writes Paro a cruel letter to sever ties, plunging himself into despair.

Seeking solace, Devdas meets Chandramukhi, a kind-hearted courtesan who falls for him as he spirals into alcoholism. Paro, unfulfilled in her marriage, remains devoted to her duties but haunted by Devdas’s memory. When Chandramukhi and Paro unite during Durga Puja, Paro’s past is exposed, and she is confined by her husband. Gravely ill, Devdas journeys to fulfill a dying promise—to see Paro one last time. He collapses outside her home as Paro rushes to him, but the gates close. She weeps helplessly as Devdas dies whispering her name. The lamp Paro once lit finally flickers out.