My Losing-Dog Self's Stepsister Is Actually My Former Youth...

[Childhood Friends + Adoptive Younger Sister] [Pure Romance] [Healing] [Younger Sister] [Slightly Yandere/Heavy Love]

Also known as "How Could My Adorable Adoptive Younger Sister Possibly Be Yandere?"

After my confession is rejected and I become the loser in love, I go to Japan to study abroad. When I arrive at my host family's home, I discover that it's the family my mother remarried into?

And that smiling girl who speaks both Chinese and Japanese and calls me "Big Brother" every day is actually my long-lost childhood friend?

I don't recognize her, but she recognizes me and pretends we're meeting for the first time. She simply says, "Welcome home, Big Brother."

"Su Nian, why have you kept this from me for so long?"

The girl answers through her tears:

"...Because I wanted to save you."