Chino Valdez is a loner horse breeder living in the old west. Partly a loner by choice, and partly because, being a 'half-breed', he finds himself unwelcome almost everywhere he goes. One day, a young runaway named Jimmy shows up at his door looking for work and a roof over his head. Reluctantly, Chino agrees to take him in and teach him the art of raising, breaking and breeding horses, until the pair finally begin to accept each other.

Although the title (which translates as "Murders in Chicago") promises a gangster story, this is more of a murder mystery that kicks off with the seemingly accidental death of a construction worker, followed shortly after by that of a noted publisher (an uneasy-looking Eduardo Fajardo). What follows is a very confusing story in which the police, a police coroner (José Campos) and a vagrant (Fernando Sánchez Polack) who witnessed Fajardo's death embark on separate inquests on what actually happened. Meanwhile, June (María Luisa Rubio), who works as a secretary for the publishing company, is under pressure by a blackmailer (Antonio Jiménez Escribano) who has pictures of her in the sack with the deceased publisher.

A man has had a werewolf curse cast upon him. If he doesn't get rid of it, he turns into a killer werewolf when the moon is full.

An innocent girl arrives as a domestic in a house where people are fueled by mutual hatred.

After marrying in Tombstone, Peggy Morgan, a rancher harassed by a railroad company that covets their land, and Alan Jackson, a gunman who seeks peace, undertake an exciting honeymoon.