Sumire and Misora ​​are mommy friends who are good friends, and they can talk about anything, including general talk, worries, and their sons. One day, as they are having a conversation as usual, the topic of sex comes up. Misora ​​is surprised to hear that Sumire has had sex with her son. Frustrated by her husband's lack of attention, Misora ​​asks Sumire for advice. Sumire is surprised to hear what Sumire has to say, but says it sounds interesting and accepts Misora's suggestion. A few days later, Misora ​​and her daughter go to Sumire's house to play, where the two naughty mommy friends...