Boku wa Mari no Naka

The manga follows an "angel-like" beautiful high school girl with a certain secret she has been hiding from everyone, and an idle hikikomori (one who abnormally avoids social contact) young man; the highlight of his day is seeing Mari at the convenience store. The story begins as Mari wakes up in her room, but something feel amiss about the room and even her own body.

(Source: ANN)