The Agency for the Prevention of Supernatural Disasters was established by the government to fight spirits. Mediums, clairvoyants, exorcists, people with strange abilities and odd appearances – risking their lives, they battle evil using the most incredible gadgets: from magical swords and pistols with holy water to motorcycles and airplanes. However, despite the bloody atmosphere and frantic drive of the first two episodes, the main events of Ga‑Rei Zero are not only about tracking and destroying dangerous monsters. The main heroines of this series are two girls, heirs to families of exorcists. The elder, Yomi Isayama, became a caring sister and largely replaced the mother of young Kagura Tsutimi, whose father was too busy to spend time with his daughter. Yomi and Kagura were always together – after school, at home, and during missions. In their lives, besides fighting spirits, there were many happy and sad moments, everyday joys and sorrows. Colleagues had grown accustomed to the "little sisters" working side by side, and no one could imagine that Yomi would raise her sword against Kagura…