Reiko and her son Makoto are bound together in a forbidden relationship. One day, Reiko's younger sister Ryoko and her son Takashi come to visit her house. Reiko provokes Takashi, who has grown into a fine young man, with her proud body and attacks his young cock... Meanwhile, Makoto is attracted to Ryoko's beauty, and the four of them devour each other's bodies, developing into an unprecedented incest drama...