The Lagina brothers are getting tantalisingly close to uncovering the secrets of Oak Island. But, just as they are preparing to descend into what may be the entrance to a treasure trove, the tunnel they've been working on starts to dramatically flood. 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?