The story narrates the journey of a young playboy named Raj Sharma (Ranbir Kapoor), who meets three young women at different stages in his life: Mahi (Minissha Lamba), a small-town girl from Punjab; Radhika (Bipasha Basu), an aspiring model in Mumbai; and Gayatri (Deepika Padukone), a non-resident Indian student in Australia.
In 1996, Raj runs into Mahi on the Eurorail during a trip to Switzerland. Mahi is a sweet, dreamy girl who believes in true love. When she misses her train, Raj helps her reach the airport through a different route. On the way, they share a kiss after Raj reads her a poem he wrote about her. At the airport, when she opens the paper on which Raj had written the poem, she finds it blank. She overhears Raj boasting to his friends about the “stuff” the pair did and is shocked and heartbroken. Raj realises she has overheard and shamefacedly leaves..