Bunny: Ranbir Kapoor
Bunny is charming and fun loving, full of spirit and an indomitable spirit of adventure. He rejects mediocrity and longs to leave his life at home behind to travel, see the world and embrace the freedom of being unattached. Passionate and resourceful, we see Bunny grow from a young student full of unconventional ambitions to a hard working videographer on a travel show, chasing and concretizing his dreams. He embraces a modern value system and wants to be answerable to no one but himself.
Naina: Deepika Padukone
Naina is a simple, good-natured and extremely focused girl. Frustrated by the restrictions she needs to put on herself to achieve her dreams of being a doctor; she impulsively decides to go on a trekking trip to Manali to give herself a break. Through the film, Naina transforms from the restricted claustrophobic person she thought she was to a free spirited woman with a newfound love for herself and comfort within her choices. She is strong and dependable and stands firmly for rooted family values.
Aditi: Kalki Koechlin
Brazen, loud and boisterous, Aditi finds herself constantly pushed into being "one of the boys". She is deeply protective to the point of being aggressive towards her two best friends, Avi and Bunny. Aditi doesn't care much for appearances or money, but extends her own brand of warmth to those she respects or likes. She is fiercely loyal and fiery, almost too ready to fight for what she believes in. Aditi rarely reveals her softer side but her freely swearing, belligerent persona mellows out over time.
Avi: Aditya Roy Kapur
Avi is a carefree, happy-go-lucky boy and Bunny's best friend. He loves alcohol, cricket and his student life. He enjoys living in the present moment and doesn't spend much thought or effort into planning his future. He is very attached, almost dependent on his best friend, Bunny who he loves deeply. His lack of a mature worldview stilts him in some ways and he remains largely stuck in his teenaged universe.
It is a story of the exhilarating and terrifying journey of four characters as they navigate through their youth; from their carefree laughter as they set off on a holiday together in their colleges days, until their bittersweet tears as they watch the first of their bunch get married.