The corpse found in the backyard threatens to put Álex back in jail. To prove his innocence, he looks for answers with a psychiatrist who treated Sara.

César refuses to tell Elisa what happened to Sara 18 years ago, so she turns to Álex for answers. Chema and Lorenzo start looking for surrogates.

Flashbacks unravel that fateful day in 2001. Although Sara’s diary seems to hold the key to her murder, a secret hidden in a wall tells another story.