Yui Kimura, a young woman bearing deep psychological scars from the traumatic loss of her parents, relied heavily on her counselor, Kanzaki, for emotional stability. This fragile support shattered when Kanzaki was murdered. Yui discovered the counselor's body after mysteriously falling asleep during a session and waking to find her dead. Confused and frightened, Yui feared becoming the prime suspect if she contacted the police.

Reeling from shock, she wandered Tokyo's rain-slicked streets at night. There, she encountered Takamizawa Kyosuke, a man identifying himself as a private investigator. He intervened, offering his help. Yui recounted finding Kanzaki's body, expressing her fear and confusion. Accepting his aid, she saw him as a rescuer in her turmoil. This encounter entangled her in the unresolved mystery surrounding Kanzaki's death.