Swati Azad and Mridula are two inseparable friends in college. Both do well in their studies, successfully complete college and get married to Ajay Lal and Milind Khanna respectively. Four years later, Prasad Saxena, another former collegian meets with a pregnant Mridula and informs her that Swati has committed suicide as she had lost her sanity. He tells her about the background of Swati's death and his suspicions that she was actually killed by the Lal family. Mridula gets hold of a Swati's diary, reads it, and concludes that the Lal family did kill Swati. She has the case reopened, files various documents in Court, and has the Lals - Ajay and his dad, Hasmukh, charged under section 302 and 34 of the Indian Penal Code. It is here that Mridula will find out that she has opened up a virtual Pandora's box - for the lawyer representing the Lals is none other than Deepak Khanna - her father-in-law. When Milind finds out he accuses Mridula of trying to disrupt the Khanna family life, and tells her that she is losing her sanity. Will Mridula find herself in the same situation as Swati, and end up dead, with her case being shown as "suicide" and closed?