It's been a year since she married her much older husband through an arranged marriage. Her husband is often away on business trips overseas for half the month, and it's her stepson Manjiro who comforts the body of the frustrated wife Kurumi. When her husband is not around, the mother and son make love to each other in the middle of the day without worrying about what other people think. One day, as Manjiro plays with Kurumi's breasts, breast milk begins to drip... and Manjiro, who hates milk, begins to dislike his mother. Kurumi's breast milk and desire continue to build up...