Helen (Sofía Sisniega), a brilliant and driven neuroscientist working in medical research, begins to suspect that her boyfriend Vicente (Axel Arenas) is concealing a secret life and being unfaithful. Driven by obsession and her background in behavioral science, Helen initiates a meticulous, hidden surveillance operation to track his every move. As her investigation deepens, she uncovers a dark web of lies, psychological manipulation, and boundary-crossing relationships that threaten to destroy her own sanity and emotional stability.