There was so much promise and the author could have literally gone anywhere with the plot, but instead she meanders around for a while and then chooses the least interesting of all the possibilities as the denouement. I was so disappointed by the ending, I can't tell you.
I really didn't like the characters that much, because, who knew, having no memory of your life means you don't have much going on personality-wise. We only get the viewpoints of three characters (two of the returned kids and the sister of the boy who is still missing) so there are three people who could have had some input to the plot but don't.
There's one character who is all set up to have some kind of psychic ability, but then it turns out that she doesn't. And her narrative was the most annoying of all. The author does this weird thing with spacing her words out all over the page, presumably to make up for the fact that no real plot or characterisation is happening.
Such a shame. This could have been great but it wasn't.