The creators of The Curse of Oak Island have packed several exciting discoveries into the season finale. The episode starts at Dave Blankenship’s house when the crew comes to consult with Dave. In an effort to solve the Oak Island mystery that has baffled explorers for 223 years, brothers Rick and Marty Lagina have discovered that the slipway built in Smith’s cove dates back to 1769, 25 years before the Money Pit was dug out. To do this, they send log samples to the University of Saskatchewan and their expert on dendrochronology, who was able to date the samples with 99.99% of accuracy.

Lagina brothers and their crew have spent months digging in Smith’s cove, trying to find out more about the stone tunnels that connect the ocean to the Money Pit but have found several man made objects instead.
After the meeting with Dan, Rick and Marty returned to Smith’s cove, where the rest of the team was busy digging. With winter fast approaching and less than a week before they have to shut down until spring, the crew is frantic about getting some answers before they wrap things up for this season. On top of that, their permits are expiring, and the entire team is exhausted. As they plow on, the team discovers another structure, made of wooden boards and packed with clay. They can’t discern the purpose of this wall and so they decide to follow it and see where it leads them. As the day ends with them no closer to a solution, experts from Eagle Canada finish their preparation for the exploration of the ground beneath the triangular swamp. By using seismic testing, they hope to find any large structures that may be hidden below the swamp. To that purpose, they have placed 2,000 explosive charges in regular intervals across the area and they are ready to start measuring the results of those explosions. Each charge consists of 20 grams of dynamite and the resulting echo is captured with geophone recorders. Marty is certain that there is some large structure below them and Eagle Canada is confident that their technology can discover it.

The next day begins with a meeting in the war room. The meeting reveals some exciting new evidence suggesting that French who have been on Oak Island are connected with Knight Templars. Not only that, but there is a clear connection between the son of the French admiral who led the expedition to Nova Scotia in 1746 and Thomas Jefferson and Benjamin Franklin. The team speculates that if the French told the Founding Fathers about the treasure, some of it could have been used to finance the American Revolution.
That theory would also explain the origin of the treasury, connecting it to feeling Templars who could have escaped to the New World from the French king Philip IV who disbanded them in the 13th century.

Another thing that seemingly connects Founding Fathers with Oak Island is a carving found on a stone resembling the Appeal to Heaven flag created by George Washington.
In the meantime, Eagle Canada has finished its seismic survey, but the team will have to wait six weeks for the data to be processed and the final report created.
The team digging in Smith’s cove continues to discover mysterious structures, and they can’t decide who made them, the people who made the Money Pit or earlier treasure hunters in an effort to block seawater from entering Money Pit. The unfortunate reality is that there is simply no time to dig further, as winter is upon them.

One final meeting is called in the war room to hash out everything they did and discovered, especially in Smith’s Cove. The team is trying to determine if there enough evidence to justify the continuation of the hunt. One key evidence is the timber dating, which sets it in 1769, but they can’t decide whether the structure was made by treasure hunters or treasure depositors. Majority of the team agrees that there is still something worth looking for on Oak Island, but the one dissident voice is Marty Lagina. He isn’t totally convinced and is mulling over pulling the plug on the entire operation. In the end, the majority view prevails and the team goes to the winter breaks with plans to return in the summer.