Rick and Marty Lagina return to Oak Island with a two-million-dollar budget and a mandate to excavate the Money Pit. In the War Room, the team sets the season's priorities: sink large-diameter steel caissons into two target sites at the Money Pit, drain the triangular swamp under the new cooperation agreement with fellow landowner Fred Nolan, and settle the lingering debate over Borehole 10-X. The first target, Valley 3, produced evidence of a possible wooden vault at the 140-to-142-foot depth two years earlier. The second, C1, is where Charles Barkhouse's prescribed drill location yielded underground camera footage of a gold-coloured object inside a 21-foot void at 170 feet. Dan Blankenship argues forcefully for 10-X, presenting chain, wire, and low-carbon steel recovered from the bottom of the 235-foot shaft, all tested as pre-1750, while Dave Blankenship acknowledges that diver John Chatterton's Season 3 exploration concluded the chamber was a natural formation and that the so-called wooden box was a 10-to-12-inch angular rock Chatterton picked up and moved. Marty proposes bringing sonar expert Brian Abbott back to rescan 10-X, reasoning that if the object has shifted position, Chatterton's account is confirmed and the matter can be closed.
Driller Arthur Jefferson begins removing old steel casings from the Valley 3 borehole to clear the way for the new excavation. One casing initially refuses to budge, raising concerns that if it shears off underground, the team may lose access to the target entirely. After sustained effort the casings come out intact. Meanwhile, area historian Doug Crowell introduces the team to New York-based researcher Zena Halpern via conference call, with Marty and Craig Tester joining from Traverse City, Michigan. Halpern presents three documents: La Formule, a coded cipher whose symbols match the Kempton characters believed inscribed on the lost 90-foot stone discovered in 1804; a French-labelled map of Nova Scotia dated 1179 that she connects to the New Ross area; and a hand-drawn French map of Oak Island dated 1347. The Oak Island map labels landmarks in French, including a basin corresponding to the swamp, a marsh, a dam matching the location where Nolan described a log wall, and an entry point labelled "the oak enter here" that aligns with the Money Pit. Three features remain unidentified: the anchors, the valve, and the hatch. Halpern traces a theory from the biblical general Joab, who served under King David, through the Portuguese Templars' presence in North Africa to a possible transport of the Ark of the Covenant to Oak Island. Crowell notes that her cipher appears to use the very same symbols as the 90-foot stone inscription, a connection he calls immediately intriguing.
Rick, Charles Barkhouse, and Doug Crowell travel to New Ross, roughly 20 miles north of Oak Island, to visit a property purchased by researcher Alessandra Nadudvari and her husband Tim Loncarich. In the 1970s, a previous owner named Joan Harris uncovered foundation walls up to five feet thick while digging a garden, along with a stone she called the Herm Stone bearing what appears to be a faint cross. Rick identifies it as consistent with a Portuguese Templar cross of the kind documented on 12th-century records. The property also contains an intricately constructed stone well with walls roughly four feet thick and stories of chambers leading off from it. Rick lowers a camera into the well and finds the stonework in remarkable condition, the walls perfectly intact with no sign of collapse. At the bottom, what appears to be a flagstone floor is visible, echoing the flagstones found at two feet depth in the original Money Pit.
Back at the Mug and Anchor Pub in Mahone Bay, Jack Begley overlays Halpern's 1347 map onto modern satellite imagery and finds a striking alignment between the old French coastline and the current island shape. Dave Blankenship reveals a strange depression near his property on Lot 22, close to where the map places the hatch, and the team heads into the woods to investigate. They find a rectangular opening in the ground that appears to have been chiseled through bedrock, and Rick commits to following up on every lead the map provides.
