Dr. Amarnath Gill, a wealthy and respected doctor, comes to the hill-station of Darjeeling for a vacation. He is received warmly by a group of local doctors, who put him up in a well-furnished, lavish old house. While in conversation with the locals, Dr. Gill reveals that this is his second visit to Darjeeling: he last came as a young medical student, 25 years ago. As Dr. Gill spends more time in town, the memories of his last visit come rushing back to him.
On his last trip, the young Gill sprained his ankle and went to the local vaid, Harihar Thapa, for treatment. He gets along famously with the vaid, and is clearly attracted to his beautiful young daughter, Chanda. Amarnath is impressed by Chanda’s knowledge of medicinal plants and her simple spontaneity. Squabbling over her father’s walking stick, the two soon fall in love with each other.
In the present, Dr. Gill asks around after Chanda’s whereabouts. He is told that she was married to a lame man named Harkari, and had a daughter, Kajli, with him. The family lived in Nili Ghati for a while, where Chanda was working at a textile mill. Invited to the opening of a clinic in the same area, Dr. Gill readily seizes on this opportunity to go looking for her. However, he finds no trace of her at the mill, and is told by the overseer that Chanda’s brother-in-law exploited her for money once her husband passed away. She went to live with the thekedaar Jodhpal along with her daughter, and lost her mind waiting for Gill to return. Still holding on to this hope, Chanda passed away eight months before Gill returned to Darjeeling. Overwhelmed by guilt, Gill embarks on a search for her daughter, but the trail runs cold very soon.
As Gill recalls the last time he saw Chanda, we are told that he asked Thapa for her hand in marriage. Deeply attached to his daughter, Thapa did not wish to marry her off in such haste, and told Gill to return after his exams. Wrapped up in his reminisces, Gill is shocked when he is suddenly confronted with a face from the past: a young, foulmouthed prostitute who is the spitting image of Chanda. Haunted by what Chanda’s daughter has been reduced to, he visits the brothel and asks for Kajli.
Though Kajli bears a striking resemblance to her mother, the harsh realities of the world have made her a brash, world-weary woman. She cannot tolerate what she thinks is pretence of affection from Amarnath, and she turns him out when he calls her “beti”. Gill’s own regret does not let him rest, and he returns to her, this time purchasing her services from the brothel for an indefinite amount of time, and takes her to his place of residence. Once there, he is disgusted by her coarse habits, and he attempts to mould her in his image of Chanda: buying her clothes, and telling her to stop smoking cheap beedis. As the two begin to form a closer bond, he tells her that he fell in love with a woman in Darjeeling 25 years ago, but as a young surgeon, he accidentally killed a man on the operating table. He went to jail for 3 years as a result, and never came back to her, fearing that she would be unable to forgive him. Though he does not reveal to Kajli that this woman was her mother, he tries to reunite her with an old lover, Kundan as repentance for his mistakes. Unfortunately, it turns out that Kundan is married.
As they return, the heartbroken Kajli tells Gill what happened to her family: driven to insanity by the false promises of the doctor, her mother’s health grew steadily worse, but she held on to the hope that her daughter would eventually become a doctor herself. Taking advantage of the two women’s helpless state, Kajli’s uncle Dinu raped her and sold her into prostitution. Despite his dastardly behaviour, however, she tells Gill that she does not solely blame Dinu for this state of affairs, but the doctor who abandoned her mother. When she sees how distressed Gill is by her tale, his compassion moves her and she begins to soften towards him.
Kajli soon becomes used to living with Gill, who treats her with the utmost respect and never makes any advances towards her. She misunderstands his steadfast affection for her, and grows to love him. Knowing the impossibility of ever sharing a life with him, Kajli is terrified of her mounting affections for him. Meanwhile, unaware of the storm he has set off in her, Dr. Gill tries to buy Kajli off the madam of the brothel. He is shocked when he comes back home to see that she has donned her old clothing again. To convince him to turn her out, Kajli tells him that she visited one of her old patrons, and her plan succeeds: angered and hurt, he tells her to leave.
Once Kajli has returned to the brothel, she realises that her heart lies with him, and she cannot make her peace with her old life any longer. She comes back to him, but Gill is aghast when she expresses her love for him. He finally discloses his true identity to her. Horrified by this revelation, Kajli tries to leave, but she is still at the gates of the house when he is leaving town the next morning. When she tearfully shows him an old photo of him her mother had treasured, Gill can no longer turn her away. They embrace, and he takes her back to the city with him, hoping to provide her the prosperous future Chanda had dreamed she would enjoy.