This is the story of Yūhi Hinomaru. Her past, when she was just about to turn 12. Before turning 12, she's just a normal girl. There's nothing wrong with her. At least, that's what she thought. The word 'lost'. What does it mean? Some may say it's like getting lost in the woods. Some else might say that it's like being lost in a very hard test. But for Yūhi Hinomaru, 'lost' means something else. Just what is 'lost'? For Yūhi Hinomaru, 'lost' is being drowned in a void of emptiness. Knowing the way, yet can't find it. Why? Many may ask. It's simply because it's the void of emptiness. Being 'lost' is something Yūhi never wants to experience again.