Ryugase Cave is a tourist attraction in Sasanaki Town. However, people say there is a vast area underground, where an unknown giant civilization exists. Wanting to see it for themselves, our brave explorers venture into the depths of the cave, and discover skeletons, bat people, and a mysterious giant creature! As they overcome several trials, our explorers collide with a shocking truth deep within the pits of Hell!! And what on earth do our explorers witness in the deepest parts of the darkness?!