For Joel and Thomas Mason, a normal school project turns into an adventure that almost costs them their lives. Along with the other 5th grade students at Crozet Elementary, Thomas and Joel have the assignment of researching the abandoned train tunnels engineered by Claudius Crozet, the man for whom their school and town was named. These tunnels are over 150 years old, and one of them hides a secret that isn't supposed to be exposed. Joel, Thomas, and their new friend, Kevin, begin their own secret investigation of these tunnels, and almost disappear forever.This story is based around the history of the Crozet, Virginia area, and the train tunnels engineered and built by Claudius Crozet in the mid-1800s. Those tunnels had been closed for over 70 years, but are now being reopened to the public for hiking and exploration.