María and Ángeles interview the adopted son of a woman named Rosa, who the Azules believe may have been the Undresser's first victim.

The Azules turn their attention to unsolved murders, hoping to find a connection to the Undresser. 

The detectives take drastic measures to find answers. María seeks the help of someone who can offer new insight: a convicted serial killer.

Romandía gets pulled into the investigation as the Azules uncover a clue that may reveal the Undresser's identity.

Another Undresser victim is found, confirming the Azules' suspicions. Their investigation points detectives to a new suspect.

Dissatisfied with the detectives' conclusions, the Azules conduct their own investigation off the books.

María and the other Azules stumble upon a new victim of the Undresser and watch as a man they believe is innocent gets arrested.

As a serial killer targeting women terrorizes the city, María, Valentina, Gabina, and Ángeles join the first female police force.