Arisa, who lives with her husband and daughter-in-law as a family of four, one day learns from her son-in-law Yohei that he has doubts about his daughter. Thinking for the sake of the couple, Arisa starts investigating her daughter's surroundings with him, but as they spend more time together, Yohei becomes increasingly distracted by Arisa's massive breasts. Gradually, the son-in-law forgets his original purpose and cannot suppress his desire in front of those obscene breasts…
