Eriko and Miki are beautiful sisters. However, Miki had a forbidden physical relationship with her real son, Wataru. And they were planning to have fun with four people by pulling in Eriko's son. One day, Miki seduces her nephew, Eriko's son, Kiyotaka, using her plump body as a weapon, and Wataru attacks Eriko. And it develops into an unprecedented mother-child swap.
