神聖にして侵すべからず

There is a mansion surrounded by walls in a street situated in a corner of the city. Ruha lives inside this tiny Falkensleben Kingdom, which only contains her and two others: Hayato and his mother Yoshino. Hayato takes care of everything from waking Ruha up in the morning to cooking and cleaning. He feels that it is the least he could do for a girl that is alone. However, as summer approaches, both of them and the small kingdom all gradually begin to change.