As Yuta Togashi throws away his past delusions of grandeur in order to start high school with a clean slate, he encounters a curious girl climbing down his balcony. On the first day of school, the same girl, Rikka Takanashi, approaches Yuta, exhibiting her own signs of 'chunibyo syndrome'. Having eavesdropped on Yuta getting his delusions out of his system, Rikka declares him her soulmate, despite him having no interest in reentering his delusions. However, he is asked by the teacher to walk Rikka home, as she had only moved in with her older sister, Toka, who lives above Yuta's apartment, the day before. Upon arriving home, Yuta helps Rikka move her belongings into her apartment. Later, Rikka manages to convince Yuta not to throw away his old belongings.