Antonio is a handsome men who loves women but flees of marriage as the devil. The pastor of his people is determined to straighten but despite amendment purposes always succumbs to a pretty girl, the problem is that he never see if girls are engaged or married before seducing them.

Inocencio Prieto y Calvo receives a letter telling him he is the heir to his uncle's fortune of two million pesos. Not being able to read he has no idea of who sent the letter or its content. So he goes to the drugstore because the pharmacist can read the letter to him. But while waiting to be helped he sees that a young girl can read. He figures he has to be able to discover the letter's content by himself and decides he will save the letter and go to school, and wait to read the letter on his own.

The discovery of a human torso thrown into a waterway, leads the viewer to observe the work of modern criminology and the task of special agents to track and record the psychopath's mentality through the elucidation of techniques present in the reality of the police investigation.