Harishchandra Khanna lives a wealthy lifestyle in Meerut, India with his wife, Maya, seven daughters, and one son. His eldest daughter has been married to a young man from Lucknow, Gopal. Harish is by profession a motor mechanic and runs his own thriving business left to him by his father-in-law. Harish only comes home on Friday evening, and leaves for work early on Monday morning. His wife, widowed sister, and nephew, Jaggu, are used to his being away for 4 days. He is delighted when he finds out that he is going to be the father of his 9th child. shortly after the birth, Harish finds out that his daughters, Kamini and Kiran, are in love with Ravinder and Mohan respectively. While Ravinder is a college professor, who lives with his station master dad, Ram Swarup; Mohan is the only son of the college principal. Harish also finds out that his nephew, Jaggu, is in love with Rekha, who is Ram's daughter. He decides to finalize all three marriages and invites all young men and woman, along with their respective parents to his house. He is delayed in reaching home but when he does get home he finds the entire Khanna family troubled and anxious. They are in such a state as they have just welcomed in their home a 15 year old lad, Sunder, who claims that Harish is his father, who spends time with them in Delhi from Mondays to Thursdays. With this shattering news, Harish must now come to terms with his hidden second marriage and family, and possibly end losing this family, as well as the marriage alliances that would have been confirmed today.
