A stunning structure uncovered in Smith's Cove perplexes the brotherhood like never before and at the Money Pit, the team finds evidence they may have discovered the legendary box believed to contain the Oak Island treasure - the elusive Chapple vault.
The treacherous collapse at H8 forces the team to strategize an exciting new approach to the money pit while Alex and Jack investigate underwater targets which may lead to a second flood tunnel system.
With the days getting shorter and only a few weeks remaining before the fellowship must suspend operations for the winter, the team is determined to excavate under the giant crane pad in Smith's Cove, confident on making a breakthrough.
In the season finale, the team is handed a shocking new theory that may connect the Oak Island treasure to the birth of a nation. However it's also the moment of truth for the fellowship as the guys decide if they will quit or continue on their journey.