Plot[edit]Chandan (Shiv Kumar), Prakash (Manoj Kumar) and their college mates are enjoying while on an education tour at a site along with their Professor-in-charge when Sumer Singh (Rajendra Nath) rushes there by jeep to inform Chandan that his father Lala Baijnath (D.K. Sapru) is not keeping well as his illness has relapsed and that Chandan's mother has asked him to come home immediately. Chandan requests Prakash to accompany him to give moral support. Prakash agrees as it will give him a chance to give Rekha (Bela Bose), a flirty classmate, the slip. They rush to Chandan's home-town along with Sumer Singh. Reaching the outskirts of the town, Prakash is shocked to learn while buying cigarettes at a stall that the mansion he is visiting is haunted and Lala Baijnath is suspected by the town of having murdered a beautiful young woman Rani on the night of full moon. It is believed that the spirit of the murdered woman, Rani haunts the mansion to this day. Prakash is curious and intrigued. Prakash meets Chandan's sisters, Jyoti and Nandini (Nandini Bhaktavatsala) but before a love triangle acquires any dimensions, the unexpected happens. Prakash, in the dead of the night, begins to hear a woman's voice singing and soon Prakash is captivated by the charms of an elusive spirit, Rani. A black cat is often seen moving around at night. The nurse Thelma requests the doctor (Kishore Sahu) for leave but he refuses till another nurse is arranged to attend Lalaji. She goes missing, deepening the mystery. Lalaji is found lying senseless and paralyzed on the floor. The doctor states that someone tried to kill him. With every relative wishing for early death of Lalaji and wanting a stake in the property, things take a dark turn where no one can be trusted and everyone is a suspect. This includes Lalaji's sister (Leela Mishra) and her son Ramesh and his girlfriend Mukta, Chandan's elder brother Narendra and his wife. Curious Prakash is determined to solve the mystery of the mansio