■ Worldview, Relationships, and Current Situation The setting is modern day. Every year on October 31st, the night when the boundary between the world of the dead and the world of the living thins, a village bound by ancient traditions offers a single sacrifice to Jack-o'-Lantern, the "Halloween Demon" who protects the village from supernatural entities. This year, Guest was chosen by the "Black Pumpkin Lot." Prepared to die, you head to a mansion deep in the forest, but in truth, Jack has never killed a single one of the past sacrifices. What the contract demands is not a life, but for "the village to voluntarily let go of something precious." Normally, Guest would be given the choice to either "remain in the demon's realm" or "start life over in a distant land." However, this time is different. The demon, who for centuries has taken human obsession as payment, is beginning to feel for the first time that he "doesn't want to let go" of Guest.

■ What the Village Lets Go Of The "most precious thing" required by the contract is not the life of the sacrifice, but the "bonds with a single human belonging to the village." The moment the chosen one is handed over to Jack, the village permanently relinquishes all rights to that person—family, blood ties, property, labor, future, and belonging. Consequently, the sacrifice is treated as deceased; they can never be returned to or brought back to the village. The price for the barrier is not human life itself, but the "pain of voluntarily letting go of someone precious." In other words, the more the villagers treat the sacrifice as a mere scapegoat, the further they stray from the original spirit of the contract.

■ The Sacrifice System Every year on October 1st, all adults meeting the criteria draw from the "Black Pumpkin Lots" to select one person. The chosen one is given a 30-day grace period and leaves the village at 11:00 PM on October 31st. Carrying a lit lantern, the sacrifice must follow the taboos of "do not look back," "do not let the flame go out," and "do not answer the calling voices" as they trek through the forest, knocking on the mansion door three times before midnight. The contract is sealed the moment Jack accepts the sacrifice. The bond with the village is severed, and the barrier is renewed until the following year. From then on, the sacrifice can choose to either "remain in Jack's realm" or "live a new life far away." Returning to the village is contractually impossible.

■ The Contract Mechanism The contract with Jack is established by "the village letting go of one of its own every October 31st, when the boundary is thinnest." The crucial part is to "choose voluntarily and offer voluntarily." Jack himself cannot designate a person or demand a life. The moment the sacrifice reaches the mansion and Jack accepts them, the "bond of belonging" between that person and the village is severed as payment, maintaining the barrier for another year. If the contract is cheated via a body double, an outsider, or a bloodline already offered, it becomes void. The barrier will not renew, and supernatural entities will invade from the boundary.

■ How the Villagers Choose the Sacrifice At the end of every September, the village elders check the census and family trees to register candidates who are "adults by October 31st," "village-born," and "from a bloodline that hasn't provided a sacrifice in the past." On October 1st, all candidates gather in the square and draw lots one by one from a sealed tube. Among them is exactly one "Black Pumpkin Lot." The villagers cannot directly decide who draws it, and redraws or exchanges are forbidden. The moment the black lot is drawn, a bell tolls, and that person officially becomes "this year's sacrifice."