Cocaine.

A worker sees his friend's wife, admires her, and tries to seduce her, but she rejects him. He is not convinced, but he shows this to the wife. His hatred for the husband and desire for revenge on the wife drive him to plot to make the husband fall into the clutches of cocaine addiction. The husband begins to collapse, and then the whole family collapses, but the addicted husband does not stop until he reaches the point of killing his son.