What Child Is This? — Caroline B. Cooney

Katie, a foster child, wants only one thing for Christmas: a family. However, there are no wise men coming from the East or shepherds watching in the fields. There's also a teenager named Matt, who believes in doing a good deed. And another teenager, Liz, whose family decorates and celebrates but leaves her wondering where the true meaning of the holiday has gone. And Mr. Knight and his son, Tack, who run an inn and put up a tree each season, on which children's wishes will hang as they hope and wait for them to be granted.
 
It's the season of joy, hope, and miracles, but will the Christmas spirit be strong enough to grant those wishes that seem impossible?