My daughter asked me to read this book, and had a copy of it for herself--it's kind of stretching to say that it was free since I paid for it, but I'll count getting a second read out of it.
The Owl Keeper is aimed at the younger end of the YA set. The protagonist Maxwell Unger thinks of himself as a sickly boy, kept at home by a nasty guardian who rules the household, including his weak parents. Turns out she has influence far outside the household, and he's not so sickly. He and a fierce girl (Artemis Rose) go out in search of the Owl Keeper to rescue their people from the Absolute Dark and the High Echelon.
What I liked best about this book was the very full and complex character of Artemis. She is strong and impetuous in the extreme, being fully herself but needing Max to provide calm and make good decisions. She made what was otherwise a much too youthful book for me a fun read.
I can recommend this for 10-12 year olds with 3 stars.