Atsushi Satou is not merely neglected by his family, but entirely ignored. He grows up devoid of human interaction, instead learning "cat language" and "dog language" from his pets. Upon entering the world of socialization with other children, his speech is impaired and his social skills lacking. He befriends a gloomy blonde, also named Satou with whom he develops an infatuation. Discovering that his first friend, Satou Manato, is gravely ill and has a twin named Shuuto, Atsushi remains a faithful friend. Years later, two new friends discover that there are two Satous in their school, seemingly identical twins at first glance. However, there is more to the situation than meets the eye.
