When her husband is transferred to another location, Mako, a mother, begins living with her daughter and son-in-law. At first, she thought the couple was getting along well, but she was shocked to find out that the rift was actually caused by her son-in-law Kunio's huge penis. Upon seeing the size of his penis, Mako's desire that lies dormant deep inside her was ignited... "My daughter's mistakes are my mother's fault," she says, and approaches him with her voluptuous body, devouring his huge penis. Unable to resist the intense temptation, Kunio continues to be swept away, and the son-in-law, who has fallen into forbidden pleasure, begins to desire his mother-in-law himself...