The horror-thriller follows a group of teenagers dealing with the disappearance of one of them, Yuki, at an amusement park's haunted house. On a rainy day 10 years later, Yuki inexplicably returns. However, no sooner is she united with her former friends than she collapses, and the group rushes Yuki to a nearby hospital. But after checking in, they discover that things are not quite as they seem at the medical center. As the night wears on, the group sinks deeper and deeper into the events from a decade ago that led to Yuki's disappearance.