Here's the cover of the new book:

The novel takes place largely in the cloud forest of Costa Rica, the Monteverde area.  Pictured are the two major child characters, Lark in the foreground and, walking away, her older brother Caleb.  If you look closely you can see that Caleb is a bit ethereal, not quite there, disappearing.  The surrounding clouds make a convenient medium in which to disappear, but the novel is also a ghost story. 

So this is really the design for the ARC, which should be printed any day now.  Look for the actual published book in April of 2013.