English dub available. Newlyweds Hyun-su (Lee Sun-kyun, Parasite) and Soo-jin’s domestic bliss is disrupted when Hyun-su begins speaking in his sleep, ominously stating, “Someone’s inside.” From that night on, whenever he falls asleep, Hyun-su transforms into someone else. Overwhelmed with anxiety about what her husband may do next, Soo-jin can barely sleep. She exerts every effort to stay awake each night, spiraling deeper into doubt about whether the person sleeping beside her is truly the person she once knew. Despite treatment, Hyun-su’s sleepwalking only intensifies, and the new family’s lives become a twisted psychological nightmare.
