Tomb Robbers: Returning from Despair and Traversing the Secret Realm

Sumu accidentally fell into a thousand-year-old tomb and was trapped in a dark underground cave for several years. Fighting alone against endless dangers and desperate situations, struggling to survive until the present world. It just so happened that others were able to escape from their troubles by exploring caves. With the skills honed in desperate situations, they traveled across the mountains and rivers to explore the hidden ancient places in various places.