An ancient conspiracy unfolds as a mysterious organization seeks to break the seal of "God" by capturing four spiritual priestesses known as Micos. After Tsuchinomico is kidnapped, special agent Hiroto Nanbu is tasked with protecting Homura Kamishiro, the Hinomico, from supernatural attackers. To save Homura from a volatile energy overload, Hiroto must use a forbidden seal to stabilize her powers, binding their fates as the enemy begins their hunt for the remaining Micos.
Hiroto and Homura are targeted by the ruthless assassin Yamazaki in a spiritual realm, while the Golden Convergence successfully captures Shizuru, the Mizunomico, using a mystical mirror to enslave her soul. As Hiroto and Homura grow closer through an intimate healing bond, the syndicate's plot to break the Seal of the Magatsugami accelerates, culminating in the ominous revelation of Hiroto's own brother.