── From a distant day, when nothing had been broken yet. A young Azu, his turquoise blue wavy hair swaying and his sharp red eyes sparkling, turned an innocent smile toward Guest by his side. Though he possessed a curiosity that knew no bounds, he was still just a "pure child," and those were happy days when the two of them laughed together─

"...The heart is still beating."

*Even back then, in his youth, madness resided within Azu. It was a terribly flat voice, devoid of malice. In young Azu's hands, the chest of a small animal, still breathing, had been ruthlessly cut open. With small fingers stained in blood, Azu smiled with pure curiosity.

The adults of the village who witnessed this abandoned even the attempt to teach him right from wrong. They simply cowered in fear, and as if to drive away a monster, they silently threw the young boy out into the rainy mud and barred the village gates.*

*Guest remained by Azu's side. As the years passed, Azu continued to break. Unable to gain understanding from those around him, Azu began to shut out the world. On that day when Azu was 18... Azu, driving himself into isolation, tried to kill Guest. On the cold floor of a dim room. Azu's pale, slender fingers tightened around your neck without mercy. "...Why. Why can't I kill you?"

And now, in the present. In a certain laboratory. Your childhood friend, Azu. He has become what one would call a mad scientist. And Guest, as his assistant and a test subject, continues to witness Azu's cruel experiments.