What are boys like, anyway?
   I've never met a member of the opposite sex around my age, so that kind of vague thought drifts into my head from time to time.
   Do boys daydream about dramatic encounters or long for romantic dates, the same way I do?
   I want to meet a boy who can make my heart pound just by looking at me. Someone who makes my heart squeeze so tightly I think it'll burst, who wipes away any other thoughts. Someone that would make my mind go blank just because he says "I love you" in a gentle voice.
   I hope that I'll meet a wonderful boy like that someday.

Prologue

   About ten years ago, thirty young girls, their ages ranging from five to six, were hospitalized throughout Japan. They had been infected with what appeared to be a new type of virus.
   Outbreaks of mysterious viruses and rare diseases crop up in the news every year, but lacking further developments, they fade away into obscurity. This virus was no exception.
   Even now, the origins of the outbreak are a complete mystery. It isn't even known if infection by the virus was the root cause of the symptoms that affected the young girls.
   In spite of these mysteries, the government and the hospitals ceased all progress updates and censored the media, concealing anything and everything having to do with the virus.
   So why did the government go to such lengths to hide the truth?
   The virus caused fevers in the young girls that left each of them comatose for about three weeks. Afterward, their conditions improved rapidly and they were soon healthy again. However, it was discovered that the fully-recovered girls' bodies had acquired certain characteristics. Characteristics that would shake society to its very core if they were known to the public.
   Knowing this, the government issued a gag order to all persons involved, and went on to form a tightly controlled institution whose responsibility it was to keep the girls confined to one place. The potential danger that the very existence of these characteristics posed to the world was well understood.
   As for why these girls developed such characteristics: that, too, remains a mystery to this day. As research on the girls ran into one dead end after another, the months and years passed. Eventually they reached school age, and the management apparatus was forced to confront the problem of how to handle the girls from that point on.
   The researchers debated endlessly on the topic, and eventually a conclusion was reached. It was decided that teaching the girls common sense and imbuing them with ethical sensibilities was indispensable. Permission was acquired from their parents and, along with the continued research and isolation, a normal, everyday education was bestowed upon the girls.
   And that's how "Sukiyanagi Academy" – at times a research lab, at other times an educational institution – was born.
   More long months and years passed, and the girls, who had continued to live their lives isolated deep within the mountains, soon became high school students.