This is the story of professor Vidhyadhhar who teaches in a college (Sanjeev Kumar). The professor smokes a lot and his wife Shobha (Asha Parekh) is fed up with this habit. The doctor sugggests that he should be put on a strict diet and exercise regime, which his wife strictly enforces on him. One fine day, a young and beautiful actress Menaka (Padmini) comes to stay as their neighbour. Thereafter, there is a verbal fight between Shobha and Menaka. Menaka wants to take revenge and decides to attract Vidyadhar to herself so that she can get back at Shobha. As the drama continues, the professor slowly gets trapped by the beauty of Menaka. His friend, professor Pyarelal (Deven Verma) was helping him so that shobha does not come to know. However, Shobha comes to find out and wants to put an end to the affair. Manda (Aruna Irani) is an assistant with the great scientist Dr. Dharam Das who invents a formula which will make one invisible. His son Ranjit Das (Dalip Tahil) is after this formula so that he can do crime and marry Menaka as he lusts after her beauty. The professor takes the formula to escape the wrath of his wife and turns invisible. What will happen to professor now? Will he be normal again? Will Ranjit succeed in getting this invisible formula?