Kimi ga Shiro to Itta Kara

That summer I was still a junior high school student. I was standing between two worlds. One day, when I woke up, I was a junior high school student in an unknown world. -Itoigawa summer. The first person I spoke to in a world that doesn't speak language is a man with with a prostethic legs and a square face. According to the man's explanation, it seems that in the summer, the world called "inner" has lost itself to this world "egg" ...!?