Present age where birthrate declined (20XX year). The body of the adult woman who did not conceive gradually changed into a motherhood constitution (Pseudo conception constitution) like conception. If "men's semen" is poured into the body, the body "There is intention of the descendant prosperity" the pseudo conception constitution is settled.

Such an inside, the pseudo conception constitution is governed as soon as possible, her dream of becoming a professional musician without becoming a full-time housewife, Kaname Otto has intentionally sex with the Protagonist. Besides, asked Protagonist to become "sperm provider" till a dream comes true...