Hiroki Imanishi, a resilient and caring high school student, navigates family financial struggles and academic pressures. His life centers on a profound, lifelong friendship with Kanata Tokino. During a stormy night, Hiroki sacrifices himself to save a young girl from an oncoming vehicle, resulting in his physical death. This act severs his spirit from his body.

His wandering spirit encounters Fhalei Rue, an ancient malevolent spirit imprisoned in a metaphysical realm. Having observed Hiroki's inner light from her purgatory, Fhalei orchestrated the accident, driven by profound loneliness and obsession to claim him. She inhabits Hiroki's vacant body, manipulating it to continue living his life.

Conscious and aware, Hiroki's spirit is forced to observe as Fhalei uses his body to interact with his friends, including Kanata, causing deep identity crisis and emotional torment. Kanata eventually senses the disparity between Hiroki's true spirit and the possessed body. This leads to a confrontation where Fhalei, enraged by Kanata's interference, uses Hiroki's body to attack Kanata near a cliff. Both Hiroki's body and Kanata fall into the sea.

Near death, Hiroki's spirit and his possessed body are transported to Fhalei's labyrinthine purgatorial realm. Here, Kanata's unwavering love and inner light counter Fhalei's darkness, resolving their intertwined fates. Witnessing this pure bond, Fhalei relinquishes her claim. She manipulates time to reverse events, restoring Hiroki to life just after the initial accident. His body and spirit reunite, and he resumes his life with no memory of the spiritual events, reunited with Kanata on a beach.

The experience underscores Hiroki as a catalyst for supernatural conflict and resolution, driven by his inherent selflessness and the strength of his bond with Kanata. His arc revolves around separation, identity loss, and eventual restoration through external forces of love confronting darkness.