The Counterfeiter's Son by Jon Musgrave

Cave-in-Rock. A nice place to take the kids...today. A couple of centuries ago? Not so much.

In the spring of 1799, river pirates and their ilk infest the biggest landmark along the Ohio River. It's not a safe place, not for beast nor man. Yet for Silas Hawkins cutthroats and counterfeiters pale against the ancient evils that lurk among its crevices and in the wilderness outside. 

After years of captivity Silas just wants to find his family. He wants to go home. 

What he finds instead he can't believe.