Based on a light novel series by Hirasaka Yomi with illustrations by Buriki.
Hasegawa Kodaka, a half-Japanese/half-British boy, has recently transferred to a Catholic High School, St. Chronica's Academy, and as always, finds it impossible to make friends there due to his naturally blond hair, inherited from his dead English mother, which makes him look like a dangerous delinquent to his prejudiced peers. One day after school, he enters the classroom witnessing the equally solitary and very abrasive girl Mikazuki Yozora while she speaks to her Imaginary Friend Tomo. They decide that the best way to improve their social situation is to form a club - the Rinjinbu (Neighbour's Club) - just to make friends and learn social skills.
Five other members soon join, starting with the school's well-connected and arrogant idol Kashiwazaki Sena, who has many male admirers but no female friends due to jealousy. Kusunoki Yukimura, a girl pretending to be a boy, who idealises and follows Kodaka in the hope that it will teach her to become manlier. Kobato, Kodaka's younger sister who is attending St. Chronica's middle school division and has a penchant for darkness, vampires and the macabre ever since she started watching an anime called Full Metal Necromancer. Shiguma Rika, a perverted underclassman and well-known scientific genius, who speaks in the third person and was saved by Kodaka during a failed experiment, thereafter trying to repay him with sex. And finally Takayama Maria, a precocious 10-year-old teacher and nun at the academy, who becomes the club adviser.