Armed with laser guns, three-fingered virtually invincible Martians collude with gangsters to invade Earth.
Mystery surrounds the ruins of an old tower house, where at select nights, a woman comes out wailing a song, amidst people committing suicide by throwing themselves off the tower. The police investigate this, but are baffled, and unable to solve this mystery. The woman is Seth Durgadas' late wife. The police interview Seth Durgadas but nothing comes of it. In the meantime, Ranjeet (N.A. Ansari) rescues Sabita (Shakila), the only daughter of Seth Durgadas from the clutches of a tiger, and himself is disfigured for life. Out of pity, Durgadas appoints him manager of his organization and wealth, and soon a greedy Ranjeet starts showing his true colors, which ultimately result in the murder of Durgadas, and the prime suspect is none other than Suresh Kumar (Ajit), the man who Sabita loves.
Bombay Police are baffled by a series of crimes - all at the hands of arch-criminal "Black Cat" who leaves his calling card at every scene of the crime. The Commissioner assigns this matter to this best plainclothes agent, Rajan. Rajan's investigations lead him to suspect Professor Gupta, who is also the brother of his girlfriend, Nita. Rajan decides to use Nita's love for him, and spies on Gupta. When Nita finds out, she is enraged at Rajan, and blames the police who she feels are covering-up their inefficiency by making a scape-goat of an innocent man. Rajan fails to prove that Gupta is somehow involved with "Black Cat", and the Commissioner gives him a deadline. If Rajan does not apprehend Black Cat within that deadline, he may be suspended or even dismissed from the police force. With no clues whatsoever as to the whereabouts of Black Cat and it's gang, Rajan has the challenge of his life, which he may not be able to fulfill.