The team drills borehole HI-4 at the Money Pit, targeting a network of tunnels detected by seismic imaging at roughly 100 feet. At 109 feet, geologist Terry Matheson identifies flat wood fragments at an angle consistent with a collapsed beam, and he and Craig Tester agree the find correlates with the Shaft Six tunnel, the passage dug by treasure hunters in 1861 who tunneled 18 feet east toward the original Money Pit before flooding and a catastrophic collapse buried everything. The core yields additional wood near 118 feet before hitting undisturbed ground at 128 feet. A second borehole, IJ-5.5, is drilled near the promising GAL-1 shaft where the team previously recovered a gold-plated British military button and an iron rosehead spike. At 111 feet, Rick Lagina and Charles Barkhouse pull a substantial horizontal beam from the core, and Craig confirms it matches the expected depth of Shaft Six. Choice Drilling operator Brennan and the crew prepare to drill additional holes to map the tunnel's direction toward the original Money Pit.
In the War Room, Rick shares news of the passing of his close friend, author and researcher Zena Halpern, who had bequeathed her entire research archive to the Oak Island team. Among the collection is a copy of the Cremona Document, reportedly authored by 12th-century Templar knight Ralph de Sudeley, describing the recovery of religious treasures from the Temple Mount in Jerusalem and a Templar voyage to the New World in 1178, more than three centuries before Columbus. Rick proposes establishing a dedicated research center on the island, and Irving Equipment arranges for its affiliate Kent Homes to donate a prefabricated building. Doug Crowell, Paul Troutman, Rick, and Charles Barkhouse begin unpacking and cataloging Zena's annotated books, maps, and documents at the new Oak Island Research Center.
On Lot 21, Jack Begley, Peter Fornetti, and Gary Drayton metal-detect the recently cleared woodland and recover a French military cap badge in two pieces, featuring a fleur-de-lis design that Gary dates to the 1700s. At the research center, Gary presents the find to Marty, Alex Lagina, archaeologist Laird Niven, and Paul Troutman. Laird connects the French artifact to the Duc D'Anville expedition of 1746, documented in ship's log pages that Doug Crowell presented the previous season. The log described a French naval force with Templar family connections constructing a deep treasure pit on a wooded island. If authenticated, the badge would represent the first physical evidence of a French military presence on Oak Island.
Construction of the 525-foot steel cofferdam at Smith's Cove progresses as the Irving Equipment crew drives 40-foot-long, 5,500-pound steel sheets up to 25 feet into the seabed. Site supervisor Colin reports that roughly a third of the wall is complete and no wood obstructions have been encountered. Rick, Charles, and Dan Henskee inspect the site and note that the cofferdam extends well beyond the area where the U-shaped structure was discovered. Author Randall Sullivan, working on a book about the Oak Island mystery, calls the War Room to discuss recent finds with Rick and Marty, who highlight the human bone fragments and medieval lead cross as the season's most significant discoveries.
The episode closes with the arrival of Davin Halpern, Zena's son, who travels to Oak Island to see the research center where his mother's life work now resides. He presents Rick with a candlestick artifact that Zena had brought back from one of her research trips. Rick promises the candle will be lit only once, when the team finds answers because of her work, and commits that Davin will be present in the room when that moment arrives. Dave Blankenship and the team observe as Rick dedicates the center to carrying Zena's research forward.
