Japan, Okinawa Prefecture, Okinawa City, Koza District. Saya is a senior high school student, and with her best friend and classmate, Kaori Kinjo, she is a member of the track and field team at school. She lost her memories of her life beyond that of the past year, but she is living peacefully with her family. His father, George Miyagusuku, runs a pub called "Omoro." She also has two brothers, Kai, hot tempered but actually kind and committed to his family, and Riku, who is good natured and loves to read. But Saya's unruffled life is about to change: when she accidentally meets a handsome cellist, Hagi, it is a sign that the wheel of fate has begun to turn...

At the experiment farm of Les Cinq Fleches Pharmaceutical, Saya is surrounded by child Chiroptera. But confronted with a mysterious humming coming from nowhere, the howling of the Chiroptera and a choking smell of blood, the girl goes berserk, and swings the sword at anything that comes into her view without even distinguishing between friend and enemy...

Saya is kidnapped by Solomon. When she wakes up in a bed in a strange room alone, it was Solomon who opens the door and comes in. Saya is alarmed and stiffens. Ignoring this, Solomon tells her, "Please marry me." Meanwhile, Hagi dashes through Manhattan to look for Saya. Meanwhile, Kai is...