Drilling begins on the T-1 shaft, the team's third and final Money Pit excavation for the season, at a location chosen by Craig Tester based on historical records placing the Chappell shaft south of the original Money Pit and at least four feet from the old Hedden shaft. Progress is slightly ahead of schedule, with the caisson reaching 82 feet and the excavation at 75 feet. A striking anomaly emerges: the water level drops to 65 feet below grade with no inflow, despite being only four feet from Valley 3, which flooded heavily. The absence of water at a depth where previous excavations typically hit booby-trapped flood tunnels suggests the team may have avoided the underground drainage system entirely. Rick and Marty watch as the spoils begin coming up, eager to reach the 100-foot level where material from the original deposit could start appearing.
In the War Room, the team revisits the La Formule cipher provided earlier in the season by researcher Zena Halpern. Working with a cryptography professor, Doug Crowell presents a partial French decipherment that yields fragments including "halt, do not hold up, dig at 40 feet with an angle," a reference to a shaft of 522 feet, and what appears to be the word "chambre," meaning chamber. Rick notes that 522 feet is almost exactly the distance from Smith's Cove to the Money Pit, suggesting the cipher may describe the relationship between the flood tunnel origin and the treasure location. The professor also identifies the cipher as one of seven pieces of a larger document, with the remaining six fragments still missing. The number seven resonates with the Oak Island curse, which holds that seven men must die before the treasure can be found.
At Smith's Cove, Rick, Jack Begley, and Dan Henskee continue excavating behind the cofferdam with archaeologist Laird Niven. They uncover a concentration of round stones packed tightly together in an area bordered by virgin soil, a configuration matching historical descriptions of what searchers found directly above the flood tunnels: layers of coconut fibre, peat, gravel, and then stones. The discovery lies precariously close to the cofferdam, and when the team considers digging deeper, they realize that undermining the large rocks could compromise the barrier and allow millions of gallons of seawater to flood the site. Rick reluctantly halts the dig until conditions are more stable. Separately, Rick and Charles Barkhouse meet Gary Clayton, the Arizona-based owner of Little Mash Island, a one-acre landmass just a few hundred yards from Oak Island. Clayton, who purchased the island in 1988 and spent a decade conducting surveys and drilling operations, presents his theory that a chamber or tunnel system runs from Oak Island to Little Mash, potentially containing several hundred tons of gold bullion.
The T-1 shaft reaches approximately 105 feet and the hammer grab brings up a large, round piece of wood that catches the team's attention. When the Money Pit was first excavated in the late 1700s, searchers reported finding nine wooden platforms made of rounded oak timbers at roughly ten-foot intervals down to 90 feet, where the inscribed stone slab was discovered. A round timber at 105 feet could represent a previously unknown tenth platform below the 90-foot stone. The wood appears significantly darker and heavier than other material recovered this season. The team cuts a section for carbon dating, knowing that if the results place it in the 1500s or 1600s, it would strongly support the conclusion that the T-1 shaft has intersected the original Money Pit.
