Sam, age 11, is an eager explorer around the farm where he lives in rural Indiana during the 1930's. His cousin Howie, age 10, comes for a relaxing visit. This visit, however, soon turns into a hair-raising adventure as Sam and Howie embark on some exploring adventures and discover some long-hidden secrets. Together they explore an abandoned log cabin on the farm and make a gruesome discovery...a skeleton in an underground tunnel. And, the skeleton is holding a large piece of metal in the shape of a horseshoe. Is the skeleton the result of a murder? Why is the skeleton holding the giant horseshoe? Are there clues hidden on the horseshoe that will help answer these and other questions? Sam and Howie soon find out that they are not the only persons seeking a solution to this mystery. Two strange men continually threaten and harass them. Why do these men want the horseshoe? Do they think it might provide clues that will lead to something valuable? Will Sam and Howie find the solution to this mystery before the strange men do? Follow along as Sam and Howie are determined to be the first to follow the clues and find the solution to the mystery of the giant horseshoe.