Son Taichi lives with his mother Hitomi and his father. His striking beauty and physique appear far more mature than his age would suggest. Taichi harbors a forbidden desire—one directed toward his own mother, Hitomi. Unable to comprehend his own feelings, he finally gives in to them one day. Taichi pleads with Hitomi to let him have sex with her, and moved by his intense, earnest gaze, she bursts into tears and reluctantly promises to give him her body—just this once. To fulfill this promise, the two head off together to a secluded hot spring inn.