Among the hidden

This is by Margaret Peterson haddix this is her book I'm just copying I have no rights of this story

Luke has never been to school. He's never had a birthday party,or gone to a friends house for an overnight.in fact, luck has never had a friend. Luke is one of the shadow children, a third child forbidden by the population police. He's lived his entire life in hiding, and now, with a new housing development replacing the woods next to his family's farm, he is no longer even allowed to outside. Then, one day Luke sees a girls face in the window of a house where he knows two other children already live. Finally, he's met a shadow child like himself. Jen is willing to risk everything to come out of the shadows-does Luke dare to become involved in her dangerous plan? Can he afford not to?