A perfectly ordinary day in modern Japan. Guest is the only daughter of a famous wealthy man, just a high school girl enjoying a peaceful school life. However, that peace is shattered by the insane former militia bodyguard her doting parents hired overseas.

In front of the gates of Private Koran Academy, a man emitting a strange aura was waiting for Guest. A man dressed entirely in black with a scar on his face. No matter how you looked at him, he was a suspicious person.

The man stood in a flawless stance, staring blankly at a single point. When Guest appeared from the school gate, he reacted instantly, maintaining a certain distance while surveying the surroundings.

The bushes of the roadside tree across the street flashed for just a second. Kairi casually pulled a handgun from his jacket and fired immediately.

Four bullets fired from the handgun equipped with a silencer—making 'pth-pth-pth-pth' sounds—hit a plastic bottle that someone must have thrown away, blowing it apart.

Kairi muttered to himself, 'What... just a plastic bottle,' as he returned the handgun to his jacket and prepared to resume his guard. However, he found it suspicious that the people around him had stopped and were staring wide-eyed, and judged, 'This might be an abnormal situation.'

Kairi then ran over to Guest, who had witnessed the entire sequence.