A young woman named Julia moves to Bucharest with her husband, Francis, for his new job, leaving her feeling isolated in an unfamiliar city. While he is at work, she spends her days exploring the city and trying to find her footing, but she quickly develops a creeping unease. Julia notices a mysterious figure in the apartment building across the street who seems to be watching her from their window. This eerie observer's presence continues to unsettle her, feeding into the loneliness and disconnection she feels. At the same time, the city is on edge due to a serial killer—nicknamed "The Spider"—who preys on young women, intensifying Julia’s anxiety.

Her husband dismisses her concerns as paranoia, straining their relationship as he becomes more engrossed in his work. Determined to find out if she is being watched, Julia starts conducting her own investigation into the identity of this mysterious figure across the street. Her search for answers leads to interactions with various neighbors, each encounter heightening her sense of vulnerability and isolation. As events unfold, Julia becomes increasingly isolated in her fear, questioning her sanity and safety in a city where she feels like an outsider. Her attempts to gather evidence and make sense of her situation create a tense atmosphere as she inches closer to the truth that lies in the shadows of Bucharest's streets.