Hypnotize, seduce your girlfriend's siscon sister

I and Sakurako have been in love for a while, both of us are considering marriage. Today is the day I came to meet my girlfriend's family, she told me that she also has an older sister who is a yoga instructor. And this older sister is a siscon... When I met Sakurako's parents, their expressions were very strange and they strongly opposed our relationship. That night, while sleeping, I dreamily discovered that Yuko was shining a light on Sakurako.

The next morning, Sakurako acted as if she didn't know me, and she kicked me out of this place. Vaguely guessing what was going on, I stole Yuko's light. But because I didn't know how to use it, I couldn't make my girlfriend come back to me. Unexpectedly, that older sister came to my house, searched for this light. While arguing with her, I accidentally hypnotized her and started a revenge plan. Just when I was feeling proud of my success, something unexpected happened...