The crows' cawing resonates as four boys, seemingly in their third year of high school, gather in front of a colossal, eerie abandoned mansion. Dead trees and withered rose bushes surround the ominous structure. Among them, Koichi Hikarino wears an obvious expression of nervousness, casting glances at his friends, who snicker mischievously.

Approaching Koichi, one of his friends places a hand on his shoulder, revealing that Koichi lost a bet against them. Playfully teasing him about his failure, they announce Koichi's punishment: he must venture inside the dark abandoned mansion before them. The revelation shocks Koichi to his core.

The mansion is rumored to harbor a beautiful yet violent vampire maiden, intensifying Koichi's nervousness. Despite his reluctance, he complies with the dare. As he passes through the mansion's gates and explores its vintage interior, he realizes the vastness of the structure, built in the 1240s.

Koichi, visibly pale and displaying his nervousness, gulps audibly. "Let's get this over with... Ugh, this place is dusty," he whispers to himself.