Ga-Rei takes place in Japan, where the Supernatural Disaster Countermeasures Division (SDCD) operates in secret to protect ordinary citizens from creatures that most people cannot see. Its agents destroy these monsters quickly and discreetly, keeping the supernatural threat hidden from the public, even as danger begins to emerge from within the organization itself.
At the center of Ga-Rei are Kagura Tsuchimiya and Yomi Isayama. After Kagura loses her mother, she is taken in by the Isayama family and grows up beside Yomi, the family's daughter. The two become inseparable, sharing a sister-like bond and serving together as highly skilled exorcists for the SDCD. But the strain of their sacred duty, the pressure of family politics, and the consequences of their work slowly pull them apart. Kagura continues to grow earnestly into the role of an exorcist, while Yomi is drawn toward a darker path. As their bond fractures, Ga-Rei turns its supernatural action into a tragedy about loyalty, grief, and the painful cost of responsibility.