This is a passionate story about a man who was betrayed by fate and fought, continued to fight, and continued to fight. Day after day, Simon, a boy from the underground village of Kiha, always took a drill to dig and was used to it. However, Simon's friend, Kamina, who was called "Big Brother", kept clamoring about the so-called world above ground. "Let's break through the sky and go to the world above ground to take a look." Kamina thought so every day. But he never succeeded. Until one day, a huge mechanical monster, "Face", broke through the village's patio and entered the village to destroy it. Confirming the existence of the above ground world, Kamina was enthusiastic and fought against Face together with the girl Yuko from the ground and the younger brother Simon. They drove the machine Simon accidentally dug out of the patio, "Naked Eye", and reached the world above ground! The surface of the earth was presented to the boy and girl, but there were actually more "faces" on the surface, and the adventure story of continuous fighting began. Simon's future unfolded in a direction that no one could imagine.