The first episode of City of Shadows unfolds in Catalonia, October 2010. The victim, Eduard Pinto, CEO of the esteemed construction firm Adcoensa, is abducted and left without food or water for nearly five days. His executioner then hurls him from the balcony of a museum and sets him ablaze, the museum being the iconic La Casa Mila, designed by the renowned Spanish architect, Gaudi.
The next day, Detective Milo finds himself lost in thought on the edge of a cliff. Having just lost his nephew, Marc to suicide, he has been separated from his wife and assaulted his boss, Sergeant Singla, resulting in his suspension. However, Judge Susana insists on his return, believing him to be the only one capable of solving the Pinto murder, asserting that the CEO was a good man.
We witness the city's division - the rich enjoying their lives in luxury while the poor sleep on the streets. Someone watches a tape of Catalonia's development, as residential areas are torn down to make way for corporate buildings.
Returning to the case, neither Commissioner Bastos nor Singla desires Milo's return. Instead, he is sent for therapy with Dr. Judith Gaig, follows Singla's orders, and partners with the new Madrid crime analyst, Rebeca Garrido.
During the debriefing, it becomes clear that the taskforce has little to go on. The killer filmed the burning process from next to the corpse and from the square. Singla also desires a resolution before the next election.
Milo and Rebeca initially clash, with Milo being rude and curt while Rebeca is meticulous in her analysis of the CCTV footage, crime scene, and burning process. However, they work in sync as Milo arrives at a conclusion. In the killer's video, Pinto's response to something is muffled. The killer appears relaxed yet meticulous, reaching the square in a short time, causing the cops to wonder if there is an accomplice involved.
They embark on a visit to La Casa Mila, a cultural landmark transformed into a bustling business hub, where the hustle and bustle coexists with the echoes of riots and protests. Antoni Gaudi's masterpiece shifts from a natural to a religious inspiration, while from its vantage point, they can gaze upon two imposing, "ugly" churches erected by the wealthy to assuage their guilt. The duo posits that Pinto's fate, like Prometheus's binding, signifies a punishment or a warning to the rest. On the square, the killer leaves a chilling signature – "G," hinting at a potential return of violence. The choice of a cleaning van with the motto "Make Barcelona pretty again" adds to the intentionality of the act.
During their first counseling session, Milo is overwhelmed as Judit delves into his past, including his father's schizophrenia and his admission into a mental institution. The situation worsens when Rebeca shares Milo's observations with Singla, who, eager for closure, angrily dismisses Milo, leaving him feeling betrayed and perceiving Rebeca as a double agent. To calm his nerves, he takes a dip in the sea but is soon overcome by panic.
That night, at the Torrens Foundation for Catalan Arts and Culture board meeting, Mr. Torrens, carrying a bag full of money, is ambushed at a red light. Judge Susana appeals to Milo to rejoin the taskforce, convinced that Torrens' kidnapping is intertwined with the Pinto case.
