Undercover reporter Casasola discovers a gruesome decapitation, and the peculiarity leads the police to rule out an organised crime motive; in a, museum, the curator Elisa is horrified to discover fresh human remains on a ceremonial altar display.
Elisa sets up an altar of the dead in memory of her grandmother Susana, unaware that the Witch entered her house; Casasola goes to live at the Griego's house, and with Elisa's help, they piece together the pattern behind the crimes.
During the early hours of the morning, the metro guards see a mysterious figure enter the tunnels. Reviewing the videos, Mondragón and Casasola manage to find the killer's sanctuary.
A body turns up on Isla de las Muñecas, and the relevance of the ritual killer case increases. Mejía and Mondragón realise that Casasola's ritual killer theory has been distracting them the whole time.
Casasola manages to get himself released, as the evidence against him is circumstantial. In addition, he realises the missing connection between the victims of the ritual killer.
Captain Peña demands that Mondragón solve the mystery of the ritual killer within 24 hours or he will remove her from the case. Casasola finds a lair, in a grotto, with the five missing heads of the ritual killer's decapitated victims.
Captain Peña continues to put pressure on Mondragón to fabricate a culprit if he cannot find the murderer. The minister is informed that the witch has been captured. A comet passes by as a penultimate omen.
Captain Peña is forced to ask Mondragón for her temporary resignation, disguised as maternity leave; she hands over her phone and badge; Elisa comments to Casasola that the penultimate omen of the Florentine Codex has been fulfilled.
