Faerieground: Hidden Things

Soli has waited a long time to be rescued from the Crows, and she is beginning to give up on her faerie kingdom and her friends. But when a mysterious letter shows up in her room, can she believe that it's truly from Kheelan?
Meanwhile, in Mearston, Lucy is tring to find out if she can cross back to the Faerieground.
Both girls are alone. And with war looming, who can they trust?