3 Idiots

Chatur Ramalingam, a successful vice-president, reminds his old college rivals Farhan Qureshi and Raju Rastogi about a bet he made with their classmate and Chatur's nemesis Rancho ten years ago. Chatur has returned to India to conclude a business deal with Phunsukh Wangdu, a famous inventor. The three go to Shimla to find Rancho, reminiscing about their time at the Imperial College of Engineering (ICE) in Delhi.
In college, Rancho was passionate about learning and often clashed with the strict college president, Dr. Viru Sahastrabuddhe ("Virus"). When a student named Joy Lobo is denied graduation by Virus for not submitting a project, Rancho tries to help finish his project for him but finds out that Joy has committed suicide by hanging. Rancho confronts Virus about the intense pressure on students, but Virus dismisses him.
One night, Rancho, Farhan, and Raju crash a wedding party, not realising it is for Virus's daughter Mona. Mona's younger sister, Pia, is initially upset with Rancho but starts liking him after he exposes her materialistic fiancé Suhas. Pia breaks up with Suhas. Virus warns Farhan and Raju about associating with Rancho, so Raju moves in with Chatur, a competitive student who relies on rote learning. Rancho and Farhan prank Chatur by altering his Hindi speech, leading to his humiliation. Furious, Chatur challenges Rancho to see who is more successful in ten years.
Before their final exams, Raju’s father has a heart attack. Rancho and Pia help save him. Virus bets Rancho that neither Farhan nor Raju will get a job after graduation. Rancho tells his friends why they struggle: Farhan's passion is photography, not engineering, and Raju lacks confidence. Farhan and Raju promise to confront their issues if Rancho confesses his feelings for Pia. They drunkenly break into Virus's house, and Farhan and Raju urinate on his letterbox. Virus notices Raju at his doorstep and threatens to expel him unless he betrays Rancho. Not wanting to disappoint his family or to betray Rancho, Raju attempts suicide but survives and is paralyzed and near catatonic for months, leading Virus to revoke the expulsion. After Raju recovers, he succeeds in the interview and gets a job, and Farhan convinces his father to let him become a photographer.
Humiliated at Raju's success, Virus sets a difficult exam to fail Raju so he cannot claim the job. With Pia’s help, Rancho and Farhan steal the exam paper, but Raju refuses to cheat and throws it away. They are nonetheless caught and are all expelled.
Following the trio's expulsion, Pia, having given the office key to the trio, finally confronts her older sister, Mona, and her father by revealing that her brother had actually committed suicide due to the pressure his father had put him through into becoming an engineer, since he wanted to pursue his own dream by becoming a writer instead, but only to simply write a suicide note.
On a stormy night, a pregnant Mona goes into labour while unable to reach a hospital, but successfully delivers her baby with Rancho's, Farhan's and Raju's help. In gratitude, Virus forgives the three, reluctantly passing down his space pen to Rancho as a mark of honor. On graduation day, Rancho disappears.
In the present, Farhan, Raju, and Chatur reach Shimla and find out that the real Rancho was a different man. Their friend was actually Chhote, the son of Rancho’s family's gardener, who took Rancho’s place to get an education and earn a degree for him. The real Rancho tells them Chhote’s address in Ladakh. On the way, they crash Pia’s wedding with Suhas in Manali and convince her to join them.
In Ladakh, they find a school run by their friend. Chatur mocks Rancho, thinking he is merely a teacher, but is shocked to realize that he is actually Phunsukh Wangdu, the person he is eager to make a business deal with. Chatur accepts defeat, and the friends run away laughing.