Invisible Girl - Lisa Jewell

YOU DON'T SEE HER. BUT SHE SEES YOU. Midnight: in an area of urban wasteland where cats hunt and foxes shriek, a girl is watching ... When Saffyre Maddox was ten, something terrible happened and she's carried the pain of it ever since. The man she thought was going to heal her didn't, and now she hides, learning his secrets, invisible in the shadows. Owen Pick is invisible too. He's never had a girlfriend; he's never even had a friend. Nobody sees him. Nobody cares. But when Saffyre goes missing from opposite his house on Valentine's night, suddenly the world seems to be watching Owen. Accusing him. Holding him responsible for Saffyre's disappearance ...