Yuu's little sister collapses and is rushed to the hospital but all the medical studies show she's healthy. Her doctor suspects a psychological trauma that she's suffered from but she can't remember experiencing one. The doctor then recommends a drug treatment called "329".

"Yuu, do you love your little sister more than anyone in the world? Madoka, do you love your older brother more than anyone in the world? This medicine can cure you but you must love each other completely."

The medication hypnotizes Madoka, leaving her open to any suggestion Yuu gives her but also makes her extremely aroused. What orders will Yuu give Madoka? Where will their relationship go?