Years had past when they last saw her. Mina was just 5 years old when that incident happen. And Yui, Myoui Yui, her younger sister, who is just 3 years old. She might be young but she clearly remembered what happen.

*flashback*

5 years old Mina and 3 years old Yui are playing in their garden together. The two really love to play with each other. Ever since Yui was born, Mina had been so affectionate to her, she love her so much. They are inseparable. Mina as an older sister always protects Yui, taking care of Yui. A responsible sister indeed. "Yui-chan, you're back is wet from you're sweat. Let Onēsan wipe it for you" Mina said. They have been playing tag and Mina notice how sweaty Yui is. "ok onēsan" Yui replied. "You know Yui-chan, you shoudnt let you're sweat dry up, you'll get sick" despite her young age, Mina was really responsible especially when it come to Yui. " I have the best sister! Aishteru onesan" Yui, being a cheeky child. She really admire her older sister.

"Mina-chan! Yui-chan!" their mom called for them. " Yes mama" the two girls run to their mother and give her a kiss on the cheek, "Mina-chan. why are you dirty? did you two play with mud again?" " Yes mama, I'm sorry mama. Yui wants to play in the mud so we play in the mud." Mina answered. " It's ok Mina-Chan. Let's get you cleaned up ok? And then let's eat some delicious Cookies!" their mom said. " yay!!" the two girls cheered as they love eating. "come on Mina-chan, you first.Yui-chan? come here inside" their mother carried Mina and gets inside to clean her. Unknown to them, Yui didnt follow her mother and stayed in the garden to play. A few minutes later, Mina was done cleaning herself when she notice that Yui wasnt inside the house. "Mama?? where is Yui???" aske Mina to Her Mother. " I thought she followed me?" her mom answered. "Let's check outside". As they get out of the house they saw Yui in the arms of an unknown man, crying. The man carried Yui to the car and before they even know it, the car drove away from their house. "Yui-Chan!!!!!"