
At his wife's funeral, Judge Cases collapses from a heart attack when questioned about her murder. Meanwhile, Marc Ramos is furious when he hears news about a copycat killer, and heads out into the night to claim his next victim.
When performing an autopsy on the charred corpse of a car crash victim, respected forensic pathologist, Sara Grau, recognizes a familiar tattoo on the burnt body: it is identical to the tattoo of a man she had a one-night stand with only a few weeks before.
As the Granny Killer follows Sara and Lluís to the hospital and is recognized by Sara as the man she had a one-night stand with, the police discover their first lead. Sara, however, is unaware of her previous tryst's connection to the recent spate of murders in the city.