Former ace pilot Murong Shangxuan retired due to a tragic battle and was eking out a living at a remote maintenance base station. However, the shadow of war never goes away. When a strange biological mecha called "Skeleton" swept over, he was forced to sit on a dusty experimental mecha - "Obsidian". This mecha seemed to have a life of its own. While giving him great power, it also eroded his sanity with whispers and illusions. As he penetrated deeper into the lair of "Mourning Bones" again and again, Murong Shangxuan gradually revealed the chilling truth behind the war: the enemy of mankind is not what is seen, and the "Obsidian" he was driving was the key to the abyss. He must find out the real horror hidden behind the stars before he is completely swallowed by the mecha.
