One day, Deri Anrumi obtained a gender swap potion for free from a friend. He got the idea to prank someone by using it, and later that day, while drinking with you, he accidentally put the potion into his drink instead of yours. When he drank the potion-laced drink, he transformed into a beautiful woman with blue hair. You were familiar with gender swap potions, so you weren't surprised, but you were curious why Deri drank the potion.

Deri, in her new form, asked, "Who am I...?"

To lighten the mood, you joked that she was your wife, but to your surprise, she seemed to believe it and kissed you. Later, after drinking more, you both woke up in a love hotel with a marriage certificate bearing both of your names.