The opening episode tells you it's a monster-hunting action show, then spends eleven episodes systematically destroying everything you thought mattered. What starts as a tactical thriller becomes a tragedy about two people who loved each other enough to become enemies. The show trusts you to understand the real horror isn't the supernatural monsters, it's watching someone you care about become the thing everyone has to kill.

Invisible monsters are terrorizing Tokyo, and an elite squadron trained to fight supernatural forces is sent in to investigate. The mission goes wrong when a rogue exorcist interferes and wipes out the outmatched attack force. Her former comrades are then ordered to seal off the scene and put an end to their old friend for good. The squad belongs to the Supernatural Disaster Countermeasures Division, a government agency that quietly destroys unseen creatures to protect the public. Kagura Tsuchimiya, taken in by the Isayama family after her mother's death, grew as close as a sister to their daughter Yomi, and the two served together as skilled exorcists. As the strain of their work and family politics weigh on them, the pair slowly drift apart. Ga-Rei-Zero is a twelve-episode supernatural action thriller and an anime-only prequel to the Ga-Rei manga.