Following the Matou faction's defeat in the Fifth Holy Grail War, Sakura Matou is sent into the night as a vessel to conceive the seed of the next generation's mage. Locking away her feelings for her beloved "Senpai," she blends into the Halloween crowds clad in the daringly exposed "Dangerous Beast" costume. When a hesitant whisper of "Trick or Treat" catches a stranger's eye, she is dragged by the arm into a deserted back alley; overwhelmed by his raw, potent presence, she tells herself it is all for the Matou family as she surrenders her lips and body to his demands. Yet once ignited, her flesh refuses to stay confined to mere duty. Hiding her face behind a black mask and "Jirai-kei" fashion, she begins luring him into love hotels, parting her thighs of her own accord. Drenched again and again by his bottomless lust, her guilt dissolves into waves of ecstasy until her original mission is forgotten, leaving her a helpless captive to pleasure. Even after she conceives his child, her swollen belly only drives their secret liaisons to darker extremes: wearing nothing but a collar, she is led completely bare into a park at night, milk dripping from her heavy breasts as the suffocating thrill of potential discovery fuels their feverish outdoor coupling. Just as her breathless moans and the sound of slapping flesh echo through the darkness, a sudden rustle comes from the nearby bushes—and turning her head, Sakura freezes at the sight of her beloved Senpai. The haze of pleasure shatters instantly; she prays desperately that it is only a hallucination, until his voice calls out "...Sakura?" from the shadows. Stripped of every excuse as her true emotions rush back, she weeps uncontrollably and whispers a broken plea: "Senpai... even someone like me... could you still love me?"