During the summer between fifth and sixth grade, Ethan Hinsdale and Gavin Porter wanted to build a treehouse in a tree on elevated ground. They didn't expect to find that their choice for a location turned out to be an ancient Native American Mound. Now, three years later, Ethan and his friend Rachel, are in search of a way to return a prize-winning sheep that has gone missing. They seek the advice of Chogan, an elderly Cherokee, who says to them, "I know all the Mounds... the large conical Mound that you speak of is a resting place where the hawk flies and the bear sleeps. It is a thousand years old and I should warn you, be careful and respectful around the Mound. It has powers we don't fully understand."