Chuunibyou (中二病) or “Middle-school 2nd Year Syndrome” in English, is a term used to describe someone who is around fourteen years old that either acts like a know-it-all adult or thinks they have supernatural powers that no one else has. This leads to them display arrogance and hipster-esque tendencies.
The series follows the life of Yuuta Togashi, a former Chuunibyou, as he tries to put his middle school past behind him and smoothly sail through high school. Yet he still has to fulfill his contract with Rikka Takanashi, who still has the syndrome, by dating her. Despite that, life is progressing well for him. However, that all changed with the return of Shichimiya Satone a.k.a. Sophia Ring SP Saturn VII, a friend from his past that is the most affected by Chuunibyou. Suddenly, Togashi's peaceful high school days end while the battle between Saturn and Jaou Shingan (True Eye of the Devil King) has only just begun.