Yukinari Sasaki is an average high school student who is frequently ridiculed by girls to the point that he developed an allergic reaction to them. As a result, he breaks out in hives whenever he comes into contact with a female. One day, when he returns home from school, he is kicked into his bathtub by his neighbor Kirie Kojima, but is transported to Seiren, a mysterious world with a mostly female population. He befriends Miharu Sena Kanaka, who ends up following him to Earth.