Shiramine Mana is sent to live with relatives in the mountain town of Sanaemachi after failing her high school entry exam. Accompanying her is her pet cat, Sasuke, who has just been revealed to be a bakeneko. But there is more to her having been sent to Sanaemachi then simply needing to study in peace and quiet.

Konakai Futaba loves her older sister more than anything else in the world. Kind, beautiful and intelligent, Ichina was everything that Futaba wished that she could be... she even encouraged Futaba when she was feeling down. As such, Futaba went to the same highschool as Ichina, hoping to be reunited after two whole years of being apart, but sadly Ichina has completely changed from the sweet, gentle sister that Futaba remembers.