Inteha (2003)

Tina Saxena lives a wealthy life-style with her widowed businessman dad. One day, all of a sudden, she gets a nasty shock when her dad informs her that he had a mistress before he was married to her mother, and that this affair had resulted in the birth of a daughter, Nandini. Much to Tina's distaste, he invites Nandini to live with them, and asks her to look after Tina after he passes away, as he has been ill for quite sometime. Mr. Saxena does pass away, leaving a grieving Tina and Nandini, with Tina still having nothing to do with her step-sister. Then a dashing young man, Ranbir Oberoi, enters Tina's life and it is love at first sight for them. Nandini also approves of him, and it looks like Tina has given up on her dislike for Nandini. After a few days, and a purse-snatching incident, Nandini counsels Tina that she should consider breaking up with Ranbir. Aghast at this sudden volte face.