Black Mail

Kailash (Dharmendra) is a shy and earnest gentleman who is in love with Asha (Rakhee), his childhood friend and the daughter of a businessman. Kailash's best friend Jeevan (Shatrughan Sinha) works for Asha's father and unknown to Kailash, is to get married to Asha. But when Kailash's scientist uncle develops a solar-powered battery that promises to make them a fortune—not to mention put Asha’s father out of business—Jeevan starts scheming. He plots to get Kailash and Asha married, only to manipulate them in hopes of getting his hands on the blueprints of the invention.