The Girl Who Wasn't There

I know what I saw. Nothing ever happens on Kasia's street. And Kasia would know. Her illness keeps her home for days at a time, with little to do but watch the world from her bedroom window. So when she witnesses what looks like a kidnapping, she's not sure she can believe her own eyes... So she sets out to find the only other witness. The girl in the window across the street. The girl who was also watching when things went down. But what Kasia discovers shocks her more than the kidnapping itself. There is no girl.