The fourth episode of City of Shadows commences with an accomplice, looking haunted from the previous episode's events, surrounded by sketches of Gaudi and victims of burn injuries. The camera then shifts to an old woman waking up for a second time, witnessing sirens racing by.
In the morning, the old woman makes her way to the church, Sant Jordi Cavaller, where she finds a smile on the accomplice's face. He recognizes her as Georgina and apologizes as he administers a drug that will ultimately lead to her demise. He then heads to work at the Sagrada Familia.
Meanwhile, at Turo de les Tres Creus in Parc Guell, the police arrive to find a burnt Torrens hanging from a cross. It is now November 1st, and another G signature and footprints are present. Singla finally accepts Milo's theory that this is the work of a serial killer.
Mauricio receives another video, which he airs. Along with the burning of Torrens, it contains a message: "Anti-system struggle is the way. We are Legion." The anchor, Julia, is jealous and accuses Mauricio of being the killer or an accomplice.
The episode then cuts to old footage of Barcelona being destroyed to make way for factories and skyscrapers. The cops arrest Mauricio for obstructing the case, but he is let go when the cameraman, Lucas, films Milo taking Mauricio aside to question him about his source. Mauricio remains tight-lipped, only telling Susana how the video was delivered to him.
In their next therapy session, Milo confesses that he can relate to the culprits' sense of being let down by the system. Judit wonders if he is drawing parallels with how he let down his nephew. He seeks comfort by visiting Rebeca, but his sister-in-law, Sara, shows up, worried that Hugo may harm himself. A flashback reveals that Hugo has schizophrenia like his father and Marc obtained the pills from him. The scene then cuts to Milo and Hugo's father taking a broken glass from his asylum room.
On top of the narrative tapestry, the reporters unleash the footage of Milo's arrest of Mauricio, their voices filled with reproach as they chastise Milo and Susana for their alleged harassment, extolling the dangers of unchecked power. In the background, a young accomplice huddles over a sketch of a burn victim, transfixed by the unfolding drama. Milo, meanwhile, finds himself rebuked by both Singla and Rebeca for his missteps in front of the camera's gaze.
As the investigation unfolds, Milo and Rebeca harbour a suspicion that the culprits are masquerading as part of Joan's movement to conceal their personal agendas and present themselves as unyielding vigilantes. Lip-reading techniques reveal Torrens' final words from the video: "You are not." Torrens believed he knew who had kidnapped him, only to be proven wrong. The search narrows in on those who were in Torrens' juvie in the 1980s and were also impacted by Pinto's redevelopment plans.
A new lead emerges when Crespo, one of the cops, notices the death of Georgina, whose house is situated near Tres Creus. They fear she may have been a witness who has been silenced. Cut to the accomplice cleaning the Gaudi cage, a flashback showing him waiting alone in Torrens' office, hinting at his history of sexual abuse as a child.
Another footage sheds light on the abysmal conditions of Catalonian orphanages, underscoring the struggle faced by children in Sant Jordi Cavaller-run orphanage and school. Rebeca and Milo meet with Father Josep, who divulges that Georgina was a protestor whose house was being expropriated by the church. He also mentions a bruise on her wrist, prompting Milo to demand an autopsy. Before departing, they run into Father Gabriel, Milo's former teacher, who holds a grudge against Milo for accusing his colleague, Father Pires, of sexual assault.
Alone, Rebeca checks on Milo, who reveals that his classmate had been assaulted. She begins to wonder if the killer shared a similar experience, positing that revenge could be the motive. She decides to stay with Milo, knowing that the killer has seen his face on TV. With five days left for the Pope's visit to Sagrada Familia, someone must be abducted and murdered that night. Coincidentally, Irene arrives just as Milo has been too busy to pick up her calls, her annoyance palpable as she hastily reveals that the buyer is arriving the next day and Milo must be present. He agrees without hesitation, earning Rebeca a judgemental stare.
The episode ends with the killer striking, kidnapping Susana after she leaves her yoga class.
