Sister-in-law is at home!

Pandit Ji predicts a change in the life of Manmohan Tiwari, an undergarment businessman. Vibhuti Mishra, a policy agent, and his wife Anita Mishra, a grooming teacher, are about to relocate to Tiwari's locality. Manmohan gets an undergarment order of INR 5 lakhs from Mr Agarwal, who is about to visit him with his wife. Manmohan and his housewife Angoori are excited. The Mishras mistake the Tiwari house for theirs. The Tiwaris mistake the Mishras for the Agarwals. A misunderstanding ensues.

As Vibhuti dreams about romancing Angoori, Anita wakes him up and asks him to get milk. On his way, he sees Angoori praying in the verandah and stops to talk. Manmohan wants to bathe, but the water supply has stopped. So, Manmohan decides to bathe at Anita's home. Vibhuti rushes to use the loo but finds it occupied by Manmohan. Manmohan pretends to fall in the bathroom, and a doctor is called. Manmohan asks the doctor to lie that his hip is fractured and that he should not be moved at all.

Dr Gupta leaves and thinks about Manmohan's plan. Laddoo, Manmohan's younger brother who can hear what people are thinking, reads his mind. Laddoo goes to Manmohan and confronts him. Manmohan bribes him with new shoes. Saxena, a neighbour, bumps into Angoori and apologises. Vibhuti slaps Saxena. Anita serves turmeric milk to Manmohan. Vibhuti cooks, and the Tiwaris and the Mishras have dinner together. Anita goes with Angoori to sleep at Tiwari's home. Saxena decides to teach Vibhuti a lesson.

Vibhuti can't sleep with Manmohan as he snores. Vibhuti eventually goes to sleep in the living room. Saxena enters Vibhuti's bedroom and beats up Manmohan under the blanket thinking that he is Vibhuti. When Manmohan takes off the blanket, Saxena has gone, and there is no one. The next day, Manmohan asks Vibhuti if he has vengeful foes. Manmohan decides to go back to his house but is unable to. Saxena overhears Vibhuti and Angoori's conversation and finds out that it was Manmohan in the bedroom.

Manmohan asks Vibhuti to sleep in the bedroom and he sleeps in the living room. Saxena enters Vibhuti's home and beats up Manmohan thinking that he is Vibhuti. Manmohan shouts, and Vibhuti comes with a stick. Manmohan thinks that Vibhuti is hitting him. Anita shouts at Vibhuti, but Angoori thanks him for curing Manmohan. Angoori sees Manmohan following Anita and confronts him. Angoori wonders what makes Anita special. Ammaji, Manmohan's mother, explains that she needs to groom herself.

As Anita and Vibhuti try to catch a rat, Manmohan enters. Vibhuti throws a fork on the rat, but it hits Manmohan. Manmohan offers to get rid of the rat without harming it. He gets a snake charmer's instrument to lure the rat, but it instead attracts a snake. Laddoo and Pandit Ji say that this snake's bite could turn humans into serpentine creatures. Manmohan finds Angoori applying ointment on her skin. He notices that her eye colour has changed and assumes that she has become a serpentine woman.

Vibhuti and Manmohan go to Pandit Ji to seek a cure for Angoori. Pandit Ji tells them that Angoori will be cured only if she bites someone. Manmohan tries to get Saxena bitten by Angoori but fails. A confused Angoori calls Amma Ji, who tells her to pray to a serpentine god. When Vibhuti goes to talk to Angoori, he finds her dancing in front of a snake's photo. Angoori clarifies what is happening. A happy Vibhuti doesn't tell Manmohan and instead sends him to Agra to look for a solution.

Manmohan sees Anita and Angoori from afar and pushes Anita behind, stating that Angoori is a snake person. Angoori informs Manmohan that she is not a snake person. Manmohan is shocked but relieved. As Angoori goes through fashion magazines, Vibhuti comes and asks her why she does not wear such clothes. He then buys a dress for her and sends it to her house via a courier boy, who ends up giving it to Manmohan. Manmohan thinks that it is from Anita and is shocked to find a nightgown in it.

Vibhuti gets a call saying that his dress was accidentally exchanged for a nightgown. He fears that Manmohan will tell Anita. Manmohan calls Anita, and she confirms that the gift is for him. When Saxena comes to seek red chilli powder, Manmohan is in a nightgown. A shocked Manmohan unintentionally ends up burning Saxena's eyes with the chilli powder. Saxena decides to take revenge. Vibhuti sees Manmohan in the nightgown. Saxena tells the neighbourhood that there is a function at Manmohan's home.

Seeing Manmohan in a nightgown shocks Vibhuti, Anita and Pandit Ji. When Anita clarifies that she had gifted a tie, they realise that the confusion has been created by Vibhuti. Vibhuti goes to meet Angoori in the morning and is shocked to find Manmohan home. Vibhuti feigns being a customer and calls Manmohan to lure him out of the home in order to spend time with Angoori. Manmohan pretends to be a policy buyer and calls Vibhuti to lure him out of the house so that he can spend time with Anita.

Vibhuti returns and says that the policy call was a prank. Anita wants Vibhuti to take up a permanent job. Manmohan finds a job for Vibhuti to keep him busy the whole day. As Manmohan is going to meet Anita, Vibhuti comes to his house with sweets and a large undergarment order for Manmohan from his uncle in London. As Manmohan is sceptical about visiting London, Vibhuti makes him talk to Saxena on the phone, who pretends to be Vibhuti's uncle. Anita agrees to groom Manmohan for his London trip.

Angoori thanks Vibhuti for helping Manmohan with the London order. Vibhuti feels guilty and decides to finish the London trip prank. Anita grooms Manmohan for his London trip. Manmohan asks Anita to teach him ball dance. As Anita is about to hold his hand, Angoori walks in. So, she demonstrates using Angoori. Vibhuti goes to Manmohan's house and informs that the trip is cancelled as his uncle has become comatose. Though Vibhuti tells Saxena to stop calling Manmohan, Saxena continues to do so.

Saxena calls Manmohan as Vibhuti's uncle to pester Vibhuti. Vibhuti tells Angoori that she should worry about women in London luring Manmohan. Angoori talks to Amma Ji, and she suggests that Angoori also go to London. Angoori informs Vibhuti and Anita that she is going to London. Manmohan and Vibhuti decide to help each other by stopping the London trip and getting rid of Vibhuti's job. Saxena continues to refer to Manmohan as Vibhuti's uncle. Vibhuti's uncle from London comes over for real.

As Vibhuti's uncle from London sits in the living room, Manmohan walks in and invites the uncle over to his place for snacks. Manmohan mentions to him their earlier telephonic conversations, which confuses the uncle. The uncle then asks Vibhuti, who informs the uncle that Manmohan has mental issues and that he should offer him a fake order of undergarments. Manmohan follows Anita for a jog. Vibhuti goes to meet Angoori and compliments her singing and hopes to sing with her.