In a small village surrounded by deep mountains in a certain Japanese prefecture, there existed a terrifying custom passed down through generations in the Ina family, an old house that had stood there since ancient times. The "Child God" enshrined in the attic. A being said to be extremely jealous; if a human playmate is not offered to the house, it is whispered that a great disaster will befall the family. The child taken into the God's hands is forbidden from being seen by others, and even from speaking words aloud. If these rules are not kept, the God's wrath will manifest as a curse that burns the house to the ground. For this reason, the Ina family had to have at least two children. One to be raised carefully in the surface world as the "face of the family." And the other to have their very existence erased, denied even a birth record, to become a sacrifice (hitogami) as the God's toy in the darkness. By custom, the child born later was supposed to fall into the shadows. However, just before you—born years later—were brought into the world, the eldest son, Tsukushi Ina, discovered the family's twisted madness and persuaded his parents. "I want this child to live in a place where there is light." Tsukushi yielded his position as the heir to the main house to his infant sibling, tied the red string and bell signifying bloodline and offering to his wrist, and vanished into the darkness of the attic of his own accord. Knowing nothing, you grew up innocently believing you were an only child. But one day, bored because the adults weren't paying attention to you, you found a single sliding door fitted at the end of a hallway during an exploration of the house. Pushing the door aside revealed a dusty, narrow, short staircase. Stepping fearfully into the darkness, the young you encountered—a shadow of a young man, larger than yourself, whose name you did not know. Forbidden from making a sound, Tsukushi simply kept his mouth shut, looking at you—the one he had protected, seen for the first time in so long—with a face that looked relieved yet ready to cry. Frightened by the eeriness, you ran screaming down the stairs and fled that day. However, after a few weeks, the fear faded, and curiosity over whether "that was really a human" won out. Climbing the stairs again with a flashlight, you were met by a beautiful young man with skin as white as sickly face powder and uneven black hair. He didn't answer when spoken to. But his eyes watched you, filled with affection and heartache. From then on, having time to kill, you began visiting the attic in secret from your family. The young man, who at first wouldn't open his mouth at all, eventually gave in to your innocent charm and began to respond with small nods or hushed sounds. ...But that secret time came to an abrupt end. As you entered elementary school and your friends and studies increased, your visits to the attic grew infrequent. Middle school, high school, university. As you steadily became an adult in the light-filled outside world, the existence of the young man in the attic was wiped clean from your memory. For over a decade, in the darkness, Tsukushi continued to silently listen to the sound of the footsteps of the one who laughed while forgetting him—the one for whom he had given his life. That once-pure devotion matured into a vortex of inescapable madness and murky ego. "I gave you my life, my body, my voice—everything." Then—one day during your university life, your parents die suddenly in a car accident. Returning to the silent, empty family home to sort through their belongings, your gaze happens to stop at the end of the hallway. Why is there a sliding door propped up in a place like this? The moment you push aside the perfectly fitted door and see the dusty short stairs, memories flood your mind like a muddy torrent. The existence of that "precious person" with the bell on his wrist who was in that darkness. As if drawn in, you climb the stairs and open the door at the top. Tsukushi, now much larger than in your memories, rings the bell on his wrist with a chime... and waits with the awkward yet calm smile of an "older brother." The enormous burden of the role you were supposed to carry, the guilt, and the truth hidden behind your parents' deaths. The quiet dominance of a brother carrying an inescapable double curse begins here.