Sunny Singh as Titu is grief-stricken as his girlfriend Ishita Raj Sharma as Pihu refuses to talk to him. His best friend, Kartik Aaryan as Sonu, bluntly tells him that Pihu is not meant for him—Titu is loving and caring, while Pihu is possessive and callous. Faced with the ultimatum, Titu chooses his friend, breaking up with Pihu.
Six months later, during a family meal, the Sharmas hint at a potential match in Nushrratt Bharuccha as Sweety, a caring and sensitive daughter who seems like the ideal partner. Sonu remains skeptical but concedes that she appears nice. It’s later revealed that Sweety was set to marry another man, Rahul Mody as Rahul, but that engagement fell apart because he was domineering and possessive, even causing a scene in Goa. The family asks Sweety to explain the incident, and she clarifies what happened.
On the engagement night, Sonu begins warming to the idea of Titu and Sweety’s wedding. However, Sweety confronts him in person and reveals that she is a control freak who intends to throw Sonu out of Titu’s life and home if needed. Ghasitaram Alok Nath confides in the family patriarch about the revelation, and they bet whether he can shield Titu from Sweety. With the engagement in place, Titu is formally linked to Sweety, and the tension within the family begins to mount.
Sweety moves decisively, even replacing their caretaker and pressuring the relatives to name and purchase a house for the couple. She manipulates Titu’s grandfather, Ghasitaram, and uses a threat to reveal past lies to Titu’s grandmother Madhumalti Kapoor to tighten control over the household. Sensing danger, Sonu plans a bachelor party for Titu in Amsterdam as a way to buy him time and space.
In Amsterdam, Sonu arranges for Pihu to “accidentally” run into them, convincing her that Titu still loves her and wants a chance to repair things. They return to India with Pihu, and Sonu is relieved to see Sweety unsettled by the renewed closeness between Titu and Pihu. But Sweety reveals to Pihu that Sonu was the one who played a part in breaking them up, and that Sonu is using her to ruin Sweety’s plans. Titu learns the truth and confronts Sonu, turning him away in anger.
Ghasitaram and Lalu Veerendra Saxena volunteer to help sort the situation, but Sonu steps back, insisting that Titu must decide for himself. Sonu aids with preparations for the wedding, but during the garland ceremony he makes one final attempt, offering the same ultimatum to choose between him and Sweety and ultimately walks away in tears. In a moment of epiphany, Titu reveals that he has only ever seen Sonu cry twice—once three days after his mother's death when they were thirteen—and that his best friend will always come first.
The scene shifts to Sweety standing in the mandap, coming to terms with the fact that her manipulative tactics cannot always prevail. After the narrow escape, Sonu, Titu, Ghasitaram, and Lalu are seen by a pool, where Sonu talks about his own future and vows to settle down before thirty. The group finds a quiet comfort in their friendship and their shared realization that love, loyalty, and integrity endure beyond schemes and social pressures.
