Mother Rin strictly disciplines her son Yoshiyuki through rigorous, no-nonsense training to mold him into an outstanding lawyer like her late husband. Yet Yoshiyuki's grades show no improvement, causing mounting stress for both him and Rin, who increasingly suffers from pent-up sexual frustration. Watching this tension unfold is Ken, Yoshiyuki's friend, who begins to sense the emotional instability within Rin. Attempting to help her regain control, Ken intervenes—only to trigger the collapse of her self-restraint. Her suppressed desires erupt uncontrollably, fixating on Ken's strong, fully erect cock. In that instant, a new, forbidden relationship begins to take root.