This is Yatagarasu’s debut work. Chihiro likes his imouto Rina, but she doesn’t want him around. In fact, Rina loves her older sister Matsuri, who in turns likes Chihiro! In the midst of this (taboo?) love triangle, their scientist parents sent them some packages and Chihiro opened them and found some weird stuff. His father returns shortly after with a strange girl and introduces her as an android named Kokoro.