DRS-021 - My sister-in-law stole my husband and son, now it's time for the mother to take back what's hers

Kozue, a housewife, finds her life turned upside down when her sister-in-law, Reiko, moves in. Reiko seduces Kozue's husband and even watches them have sex with a twisted smile. When Kozue realizes Reiko is setting her sights on her own son, she decides she's had enough and prepares to fight back.