Saya infiltrates a girls' boarding school, the Lycee des Cinq Fleches. Hagi too sneaks in, disguised a gardener. Saya learns from her roommate Ming about a legend of a phantom who fell in love with the prettiest girl from the school and who presented her with a blue rose flower.

An annual ball is being held in the lycee. Students, guardians and guests in formal attire are gathered in the school cafeteria when Saya arrives in a dress she borrowed from Min. On the dance floor, Saya meets a young man named Solomon, who asks her for a dance. As the music starts, David reaches the entrance to the basement surrounded by blue roses...