The team welcomes Vanessa Lucido and ROC Equipment to the island, where they will work alongside Soletanche Bachy Canada to place seven-foot caissons at several locations to a depth of more than 200 feet if needed. The first target sits directly above the suspected location of the Chappell Vault, and ROC will use an 18.5-ton hammer grab to extract spoils. The following day, Rick Lagina addresses the group in the Money Pit and names the first caisson True Believers; Doug Crowell marks the designation TB1 on the shaft. Rick asks Katya Drayton to start the oscillator. By the next session, Vanessa reports a depth of about 87 feet. The hammer grab produces wood and beams, including a piece Terry identifies as a possible support beam and a second that is hand-cut and tapered. Katya scans the spoils before they head to the wash plant and pulls out a large spike. Rick examines it, confirms it is wrought iron and extremely heavy, and sends it to Emma Culligan for testing.
In the swamp, Rick, Alex Lagina, Katya, and Billy Gerhardt continue working in the northern section. Rick pulls a board from the "steps" recently found and discusses the size of the boards with Alex, noting the absence of nails. As Billy removes more dirt, Rick spots a piece of shaped wood buried three feet deep. The group agrees Laird Niven should examine it. The next day, Alex finds another board and digs to its end, where a rock sits at the same level. Billy scrapes away the soil and exposes a large rock with another sitting even lower. Alex calls in Dr. Ian Spooner, who examines the feature and concludes it is similar in construction to the stone road.
On Lot 5, Jack Begley joins Fiona and Todd at the round feature, where the team is trying to determine whether a gap in the rocks is an entranceway, the only part of the structure where Money Pit soil has been found. Fiona recovers a small hinge, and the two discuss whether it came from a small door or a chest. Todd later unearths what looks like a diamond or piece of cut glass, which will go to the lab. At the wash plant, Rick, Billy, and Scott arrive to begin separating and searching TB1 spoils. Derek Couch finds an artifact and calls Charles over. Charles texts Rick, who inspects the piece and sends it to the lab.
Carmen Legge examines a metal artifact recently found on Lot 1. He tells the team the pin is very old, beaten out from a blob of iron, with fiber patterns that are not consistent throughout, ruling out production from round stock after 1760. Carmen says it would have been used to grab and hold something heavy, such as a boulder, and the bend indicates it was under stress. Emma reports the iron came from a blast furnace and contains some manganese, though not consistently enough for her to place it in the 1600s; she dates it to the mid-1700s. Carmen narrows his estimate to the early 1700s, possibly 1720 to 1730. The next day, the team hears results on the glass gemstone from Lot 5. Emma finds a concentration of lead not seen in modern glass and describes the composition as exceptionally clean and controlled. Laird identifies it as flint glass, ground up and pressed into a mold using a process developed in early 18th-century France by jeweler Georg Fredrich Strass. Strass combined bismuth, thallium, and lead with ground glass powder to create a paste-like substance that was heated and molded into an artificial gemstone. Laird notes this style of jewelry was fashionable in French high society. Emma places the introduction of the crystal at 1734 and adds that this piece contains 10 percent more lead than glass from the mid to late 1700s. Marty Lagina observes that the timeline fits the duc d'Anville's expedition.
