In a world where people's emotions manifest as shadowy, humanoid figures known as Umbra, Kaito discovers they have the ability to see and manipulate these entities. As Kaito navigates this complex world, they must confront the darker aspects of human nature and the blurred lines between reality and the Umbra. With the Umbra growing more aggressive and violent, Kaito's unique abilities make them a key player in uncovering the truth behind the mysterious force.