Set in 1940s Calcutta, Qala is about the tumultuous relationship between an aspiring singer and her domineering mother. The movie begins with Qala Manjushree (Tripti Dimri) who has just won the "Golden Vinyl". She is being interviewed by several journalists who mention her brother whom her mother tried to launch into the music industry 9 yrs ago. Distraught, Qala replies that she has no brother. In a flashback, her mother Urmila (Swastika Mukherjee) who was pregnant with twins gives birth to Qala, but her brother does not survive (as Qala was stronger and took away the nutrients from the weaker sibling in the womb). Urmila attempts to smother Qala, but Qala survives. Urmila teaches Qala the art of music but warns her against being a courtesan. Urmila warns Qala that as a girl she will have to work harder to be successful in the world. She really wanted a boy to carry forward the legacy of her husband, who was a music maestro.In the present, Qala is haunted by visions of a teenage boy who accuses her of taking what is rightfully his. A doctor advises Qala to rest. Urmila has ignored all attempts by Qala to get in touch with her. Qala seeks acceptance of her honor by Urmila, but is only met by a stony silence. She doesn't drink milk and is using sleeping pills to get some shut eye. In another flashback, Qala is being taught music to perform in 3 days but Urmila chides her and accuses her of not working hard enough. Urmila locks Qala out in the freezing snow. At the performance, few people show up (as Gandhiji was visiting the area and the masses had gone to attend his rally) and Qala is upstaged by an orphan, Jagan (Babil Khan), the same teenage boy from Qala's visions. while Qala's performance was in front of an empty theatre, it got full when Jagan was performing. Urmila takes a liking to Jagan's music and brings him home to live with her. Qala is jealous of Jagan. It was Qala's duty to serve milk to Jagan. Urmila wants Qala to become Jagan's assistant singer during his performances.In the present, a renowned singer - Chandan Lal Sanyal (Sameer Kochhar) dies. In another flashback, her mother seduces Sanyal (Qala sees Sanyal in Urmila's chambers at night and Urmila in various stages of undress) to obtain a chance for Jagan to sing with him. Jagan knows that working with Sanyal in the film industry can lead to working with Sumant Kumar and even a golden vinyl. To further Jagan's career, Urmila attempts to marry Qala off but Qala declines. Qala wants to marry Jagan, so she can stay with Urmila, but Urmila is disgusted by the thought of a sister marrying her brother. Urmila hosts a party and invites several influential people. At the party, Qala feels invisible but is noticed by Sanyal, whom she kisses. Unfortunately, Jagan falls sick during his performance and cannot sing so Qala sings instead, impressing the guests. Jagan gets sicker to the point of losing his voice, but is cared for by Urmila. Sumant Kumar comes to Urmila's home and wants to sign Jagan for his next song. He is confident that Jagan will sing again. Qala seduces Sumant Kumar (Amit Sial) (in the same way that Urmila seduced Sanyal) to obtain a chance at recording a song, taking Jagan's place. That night Jagan talks to Qala one last time before he hangs himself in the forest. The next day, Qala discovers his body and hugs his corpse. Her mother is distraught and cradles Jagan in her hands.In the present, Sumant begs Qala to sing a song for his new film, but she even refuses to meet him. Qala makes a call to Urmila and begs for her help, but she hangs up on her.In flashback, Urmila and Qala have a fight during which Qala calls Urmila a courtesan. Urmila forbids Qala from coming back to their house ever again. Qala leaves for Calcutta for her recording session with Sumant. She is nervous and cannot sing even on the 11th take. She was forced to provide oral pleasure to Sumant, for a last chance. She recalls Jagan, who used to sing for himself. Taking his words into account, she successfully records the song. Qala slowly rises to fame as a singer. During this period, she continues to be a sexual partner for Sumant.She becomes close with Majrooh (Varun Grover), the songwriter who advises her to cease her arrangement with Sumant. While being interviewed by journalists again, she sees a vision of Jagan. While recording a song, she breaks down and sees snow falling all around her. Her mother hears her interview being broadcast over the radio. In a flashback, it is revealed Qala dropped a globule of mercury into Jagan's milk before his performance, leading to his cough and subsequent loss of voice. Now, Qala attempts to kill herself by overdosing on sleeping pills. Her doctor Dr. Banerjee (Abhishek Banerjee) calls her mother and informs her of Qala's suicide attempt. Her mother comes to Calcutta and sees that Qala has hung herself. Her mother tearfully listens to Qala's vinyl which she had sent to her in Himachal Pradesh.