'Kyun! Ho Gaya Na' is a situational romantic comedy -- a simple story about love and life. Diya Malhotra is an idealistic, sensitive girl whose childhood was spent in the coffee plantation town of Coorg. Her father, who single-handedly raised Diva after his wife passed away, decides that Diva should travel to Mumbai to help his friend Raj Chauhan, a confirmed bachelor, run a small orphanage that he has in his home. Diva will stay at the home of the Khannas, who also are friends of her father. Diva then meets Arjun Khanna, a seemingly free-spirited, fun-loving, adventurous guy. The two soon realize, however, that they will be staying in the same house since the Khannas, her father's friends, are Arjun's parents. The friendship that develops between Diya and Arjun and their opposing views on love and marriage are at the heart of this film.