Miki lives in a two-family home with her daughter and son-in-law. They get along well, but too little sex with her own husband leaves her increasingly frustrated. When she accidentally sees son-in-law Shinichi's huge, impressive cock, she becomes obsessed and can no longer control the urge to drain him wherever they happen to be. Faced with his mother-in-law's nonstop seduction—and stuck in a sexless marriage himself—Shinichi finally gives in and devours her voluptuous body.