Namak Issk Ka revolve around an item girl named Kahaani (Shruti Sharma); who goes by the name of Chamcham Rani and a rich businessman Yug Pratap Rajput (Aditya Ojha) who are childhood friends who got separated in an accident. Yug and Kahaani meet after 15 years. This is when Yug comes to know that Kahaani is an item girl. Yug hate item girls as an item girl was the cause of the accident that happened 15 years ago.
It is later revealed that Yug’s father had an affair with, and later left their family for an item girl, which further fuels his hatred towards Kahaani. Kahaani on the other hand, is separated from her mother and father, Ravikant, husband of Iravati who does so after learning about Ravikant’s affair with Kahaani’s mother. The accident leaves Ravikant handicapped, who Yug takes care of like his own father.
Kahaani enters Yug’s house as a nurse to earn money to care for her siblings, Rani and Lucky who requires an oxygen cylinder to breathe. She also meets Raunak (Rony), Yug’s brother who is a film producer who instantly falls in love with her, despite being married to Rupa, Kahaani’s step-sister. He also proposes to her, however she rejects this as she sees Rony as a friend. Rony continues to lust for Kahaani as Rupa is not his choice and has a scarred face.
Kahaani meets Ravikant and feels a connection to him, unknown to the fact that he is her biological father. Eventually, Yug finds out Kahaani is the nurse while her mask breaks. He tells her to leave and she says she has no intention of coming to the house. She leaves and Saroj and the whole family explain how just because Kahaani is a dancer does not mean she is a bad person.
When consoling Lucky, Kahaani looks for the key that Yug gave her 15 years back which went missing, and has to go back to Yug’s house. That same day is Rupa and Raunak’s wedding anniversary and a mysterious person who knows about Iravati’s deeds messages her saying that they are going to harm Rupa. A gunsman, disguised as a waiter, aims at Rupa, whilst Ravikant begins to show distress having seen the gunsman but unable to express this in words. Kahaani sees him and looks to see the gunsman; Kahaani saves Rupa but suffers a wound to her arm in the process.
She falls unconscious and the family take care of her. She wakes up and leaves but is stopped by Yug as he promised Rupa that he would make sure she stayed. Kahaani falls unconscious again and Yug takes her in his arms and places her on the bed. Whilst unconscious, Kahaani explains how Yug misunderstands her and says whether her being a dancer puts a question on her character.