Roger Fortin reports 250 gallons of water per minute flooding the Garden Shaft. Rick and Marty descend to inspect the damage and examine the timber-filled void Dumas discovered the previous week. Rick pulls out a piece and believes it is original Garden Shaft construction material. Dumas begins pumping multi-urethane into the void, a compound that expands up to 20 times its volume to seal the water source. Paul Cote reports that overnight the shaft takes on 15 to 20 feet of water that must be pumped out before work can resume each day. Meanwhile, the team receives permission to drain the swamp and Billy begins excavating near the end of the stone road. On Lot 5, Jamie finds a small ring and a decorative metal piece that could be from a door or chest, adding to the growing collection of artifacts chemically linked to Sir William Phips.
In the War Room, Scott Clarke, a 32nd-degree Freemason, presents research connecting Andrew Belcher, assistant to Sir William Phips, to the island. Belcher was likely among the first Freemasons in North America, and Clarke argues the Belcher family knew about Oak Island. His key discovery is a 1762 map from the Archives of Canada by Nova Scotia's chief surveyor Charles Morris, also a Freemason, which Clarke believes is the earliest map of Mahone Bay showing Oak Island. At the time Morris surveyed and divided the island into lots, Belcher's grandson Jonathan Belcher Jr. served as Nova Scotia's Lieutenant Governor and Grandmaster of the Provincial Grand Lodge. Clarke noticed Morris used an unusual letter "A" with a V-shaped crossbar that differs from the standard crossbar used elsewhere on the same map. Templar researchers in Portugal associate this symbol, which closely resembles the Masonic compass and square, with the Holy Grail. The Masonic "A" points directly at Oak Island, 33 years before the Money Pit's discovery. Clarke then identifies three more Masonic A's in the name "St. Margaret Bay" whose arc, when extended into a circle, passes over the map's compass rose and directly over Oak Island. He has not found this style of "A" on any of Morris's other maps but has located it in Templar chapels and churches in Tomar, Portugal and at the Santa Maria Nuova church in Viterbo, Italy.
In the swamp, Gary pulls out a large dowel from the spoils that is similar to those found in the U-shaped structure at Smith's Cove, discovered by Dan Blankenship in 1971. On Lot 5, the team outlines the buried foundation revealed by the magnetometer survey: at 30 by 45 feet it is the largest foundation found on the island. Jack notes it predates the 1762 survey and appears to have been demolished and intentionally hidden. Jamie locates a carved stone with rounded edges that Rick confirms is manmade. Jamie tells Rick she believes a structure once stood here and was collapsed in on itself before being buried.
Back in the swamp, Billy hits rocks while excavating near the stone road. Gary gets a hit and pulls out a hand-forged chain with a large hook that he dates to before 1840, noting its size suggests it was used to unload cargo from a ship. A second scan produces another hook that Rick says Emma will need to date. Steve arrives to check elevation readings on the newly exposed stone and confirms a 2 percent slope consistent with the known sections of the road, though more needs to be uncovered to be certain. Rick and Steve discuss the possibility that a widening in the road could be a turnaround area for oxen hauling cargo.
