Chap 1: Who am I?

What if, One day, Yui saved a boy in the forest. The boy appeared to be human, but the Sakamakis seems to do not know the boy's sent, like he never existed. Yui tries to hind the boy from the brothers. Will she succeed? And who is this mysterious boy? (In this story, Yui is just a simple, innocent girl. And I have very bad English. And.. I don't know the story that much. Sorry.) Warning: Yandere containing