While investigating the link between Nicandro and Dr. Alanís, Álex uncovers a key suspect. Rodolfo asks Álex to help him bring his father to justice.

Sara tells Nicandro's dad about his son's drug business. Reinaldo offers Marifer a deal. Álex secures protection for Chema. Nicandro visits Daniela.

Lucía's arrival takes Álex's investigation in another direction. A new lawyer takes Chema's case. César shows up at Álex's house to reclaim his money.

Álex fights for his life in the hospital. A distressed Chema asks his mom for help. A flashback shows how Sara became the focus of Reinaldo's experiment.

Worried about her treatment, Sara attempts to expose Reinaldo. Chema is admitted to the Medusa Center. César reveals crucial information to Álex.

César pays a visit to Tonya and resorts to a drastic method to get information about Sara. Under Reinaldo's watch, Chema undergoes horrifying treatment.

When the truth of what happened to Sara is finally exposed, Álex unleashes one last act of revenge on the Medusa Center.