Ruth, a university student, wakes up reborn three hours before she and five friends enter the forbidden "Death Cave." In her past life, the entire group was slaughtered by terrifying skeleton monsters deep inside the cave. Desperate to change their fate, Ruth tries to stop the trip, but her friends—hungry for social media fame—mock her, and her boyfriend Sean drags her inside by force. As they venture deeper, nightmare obstacles erupt: shriveling bone monsters, poisonous spore-mushrooms, and treacherous underground currents. Under extreme pressure, the group’s morality collapses: Sean shoves his companions toward the monsters to save himself and uses others as stepping stones. Armed with past-life memories and sharp instincts, Ruth protects her only loyal friend, Rebecca, navigating through deadly traps to escape via a subterranean river. However, upon reaching safety and reporting the tragedy, they uncover a chilling truth: all records of their four dead friends have vanished from government databases, school files, and even their own photos. The Death Cave doesn't just devour human flesh—it erases their very existence from reality.
