In an age when the corners of the world have been scoured for their secrets, only one place remains unexplored-a massive cave system known as the Abyss, filled with monstrous creatures and lost relics. Those who delve into its depths are known as Cave Raiders. A young orphan named Riko dreams of following in her mother's footsteps as a Cave Raider, and when she meets a strange robot while exploring the Abyss, she is one perilous step closer to achieving her goal!
IN THE BELLY OF THE ABYSS

Riko and her friends have joined forces with Hail Hex and at last set foot in the Seventh Layer! Not long after, they find themselves trapped and under attack by a mysterious invisible force. Will they live to continue their journey or have they finally reached its deadly end?