Yukinari Sasaki is the main character of the series. Due to his small stature and timid nature, he has been bullied by girls throughout his life, leading to an allergic reaction that causes hives whenever he comes into contact with a woman. In two instances, he loses consciousness after being hugged or touched by a girl's breasts.
One day, Yukinari falls into his bathtub and is transported to the alien world of Seiren, a planet where men make up less than 10% of the population. Upon arriving in Seiren, he meets a young girl named Miharu who, for some reason, does not trigger his allergic reaction upon contact.
Yukinari has a tendency to be in the wrong place at the wrong time, which often results in him getting kicked, punched, and beaten up by Kirie during various "close encounters." In the anime, he lives alone.
