Hikaru, a beautiful wife struggling with infertility, reluctantly accepts a womb examination from her gynecologist father-in-law. Under the cover of medical treatment, his persistent fingers rub every sensitive spot until she leaves each exam soaked and climaxing. Though she knows it is wrong, she becomes addicted, loses interest in her sexually weak husband and craves only her father-in-law's cock. He trains her into a submissive sex toy who even climaxes hard enough to lose bladder control, and their private examinations become days of repeated creampies. When she finally conceives, the identity of the father remains uncertain.