The mother lives separately, and the family consists of her two sons and their father. One day, their relatives, the voluptuous and promiscuous Yariman sisters, visit their home. The sisters had come to Tokyo with the intention of aggressively pursuing handsome men, but it seems they were unsuccessful, encountering only herbivore men. Unable to calm their desires, they resort to using the brothers, whom they had previously treated as sexual toys, to relieve their pent-up sexual urges.
