Gary Drayton and Alex Lagina are amazed when they discover a nail embedded in a fragment of wood. Their discovery gives credence to the theory there was a 17th century dam situation on the site. Rick, Marty, and the team return to Oak Island and immediately uncover evidence of a mysterious tunnel in the Money Pit. The Fellowship gets a clear look at an underground structure. Are they closer than ever to solving the 227-year-old mystery?