Dalia, a 42-year-old train operator for the Mexico City Metro, experiences a sudden rupture in her life when her husband mysteriously vanishes without a trace. As she navigates bureaucratic indifference, systemic negligence, and police investigations, her personal and professional life begins to collapse. Caught in a whirlwind of suspicion and sorrow, Dalia attempts to maintain stability for her two teenage children while continuing her demanding job and dealing with the emotional strains of her personal life—including an extramarital affair. The dark, subterranean tunnels of the metro mirror her deep psychological descent as she confronts the painful reality faced by families of missing persons in Mexico.