The Skerries by J. Howard Hall
Approx. 69,160 words.
Published on December 29, 2011.
While snorkeling in a Minnesota lake, teenagers Anya and David find two stones etched with ancient symbols. When one is stolen and the other is lost in the lake, the kids resolve to recover them to prove the true history of the first explorers in North America. But powerful forces are working to prevent the stones’ secrets from being revealed. Who is after them? And why?