Exit 8

While on a subway, a man (dubbed the Lost Man) witnesses another man scolding a mother for failing to calm her crying baby. The Lost Man then receives a call from his ex-girlfriend, informing him that she is pregnant with his child and asking him what to do. He loses connection while trying to exit the station, and finds himself in a deserted, endlessly looping corridor. Reading a set of instructions, the Lost Man learns that he needs to reach Exit 8 by turning back whenever the corridor has an anomaly and moving forward when there is none. Anomalies can range from faces on posters tracking his movements, to blood raining from the ceiling. Any mistake returns him to Exit 0, resetting his progress.

Upon reaching Exit 5, the Lost Man receives a call from his ex, who continues to implore him to help her reach a decision. He relays the altercation on the train that he had witnessed, recounting that nobody defended the woman. He tearfully confesses that his failure to stand up for the woman makes him feel unfit to be a father. His ex then appears in the corridor, revealing her to be a mere anomaly and thus sending him back to Exit 0.

Eventually, the Lost Man meets the Boy, a small child who had been following the Walking Man, an unresponsive entity the Lost Man sees walking down the corridor in every loop. The Walking Man used to be similarly lost, but became part of the loop after abandoning the Boy for a false Exit 8. Although initially mute, the Boy proves highly perceptive, and with his help, the Lost Man makes steady progress. The Boy gradually opens up to him, confessing that he ran away from his mother, and gives him a hermit crab shell for good luck.

Upon reaching Exit 6, the corridor is suddenly flooded. After having a vision of himself, his ex, and their son—revealed to be the Boy—at a beach, the Lost Man tries to save the Boy, holding him above the water and comforting him before he himself is swept away. After regaining consciousness, the Boy turns the corner to Exit 8. The Lost Man appears a short while later; initially doubtful on whether it is the real Exit 8, he sprints toward it upon remembering the Boy's shell. This returns him to the real world, where he calls his ex, promising to meet her at the hospital. He enters the same crowded train he had taken earlier and once again witnesses the man berating the mother and her crying child. However, this time, the Lost Man turns to take action.