Fifteen-year-old Iwaki Tomonori, with a penchant for older women, harbors a crush on his teacher only to discover her engagement. Crestfallen, he returns home to encounter Rizel, a 12-year-old girl the government has unexpectedly wed him to. Unveiling Rizel's bioengineered origin, Iwaki's life takes a peculiar turn as her 'papa's offer financial reprieve in exchange for her residence in their home.