I am a kidnapper.

I abducted Homare when he was three years old, and for ten years I raised him while pretending to be his real older sister. Homare has no memory of being kidnapped, and he believed I was truly his sister.

But one day, he happens to find a missing person article with a photo of himself as a young child. From the name and the mole on his left cheek, he begins to suspect that I might be the one who kidnapped him.

Homare quietly probes into my past, all while pretending to know nothing.
If I really am a kidnapper, he would despise me. Even so, when he thinks of the fact that I raised him for ten years and the love I've shown him, he can't bring himself to hate me so easily.

—Who am I, really, the one he has always called "big sis"?