Anna, a mother, lives with her two sons, Takahiko and Shuji. On the surface, they live a happy family life, but Anna and Takahiko, the eldest son, have a secret. Despite being mother and son, they are in a physical relationship. The fact that they were separated due to family circumstances has only strengthened the bond between them... However, by chance, Shuji, the second son, sees them. Shuji suddenly becomes distant and tries to distance himself from the two, but Takahiko takes this opportunity to desire Anna even more...