In the War Room, the team turns its attention to the Oak Island swamp. Dan Blankenship reports finding metal stake markers, wooden posts, and oak tree stumps during earlier explorations of the area. Oak trees cannot grow in standing water, and stumps beneath the swamp would support the theory that it is man-made, created to conceal something below. Fred Nolan's survey map is consulted as the team prepares to drain the roughly 4.5-acre swamp using two pumps generating 190 horsepower and moving approximately 1,800 gallons per minute. Marty warns the group about the danger of hydrogen sulfide gas, a colorless compound that occurs naturally in the swamp. At high concentrations it deadens the olfactory nerves and a single breath at lethal levels causes instant paralysis and death. The team agrees that no one enters the swamp alone and that gas detectors must be carried at all times.
Rick receives a call from Lee Lamb, eldest daughter of Robert Restall, whose father and brother Robert Jr. were killed on Oak Island on August 17, 1965. Lee travels to the island with Andrew DeMont, the only living survivor of the tragedy. The Restalls were motorcycle daredevils who performed the Globe of Death at county fairs, crisscrossing a metal cage at 65 miles per hour. Robert's fearlessness brought him to Oak Island in 1959, where he settled with his wife Mildred and sons Bobby and Ricky to search for treasure. On the day of the accident, Robert was overcome by hydrogen sulfide while checking a 27-foot shaft and fell into four feet of water. Bobby and four others jumped in to help and were overcome as well. Only Andrew DeMont and Leonard Kaiser survived. Andrew tells the team he found Bobby still holding his father by the shoulders above the water long after the gas had made rescue impossible.
Before leaving, Lee meets privately with Rick and gives him Bobby's handwritten journals and a map. Bobby was 18 when he kept the daily logs, documenting the expedition in remarkable detail. The journals reference the 1704 stone, found as part of a man-made reservoir at Smith's Cove that fed the flood tunnels. Bobby also wrote about a "mystery box" or vault that Jack Adams, a 1930s island caretaker, claimed was buried beneath the swamp. In the winter of 1962, Bobby and his father discovered a spiral-shaped tunnel in the Money Pit winding clockwise at roughly 104 feet below the surface. They spent the next two and a half years trying to access the tunnel. Bobby's last journal entry is dated August 16, 1965, the day before he and his father were killed.
Rick and Marty invite paranormal investigators to the island before draining the swamp. Dan Henskee recounts a 1973 experience in which he believed the spirit of a dead priest whose throat had been cut entered his body while working on 10-X. The legend of pirates killing a person so that the victim's spirit would guard buried treasure has long been associated with Oak Island. Investigator Linda presents photographs from near 10-X showing what appears to be a skull-like image. In the swamp, K2 electromagnetic meters register strong hits, and several team members describe feeling watched and uneasy, though no definitive explanation is offered.
With permits secured, the team begins draining the swamp, running hoses uphill so discharge water filters through grass as required. During earlier probing, Dan and Dave Blankenship located a smooth stone roughly three by eight feet with no silt on its surface, though they could not find it again the following year. Dan also claimed a tunnel runs from the ocean to the swamp, possibly connected to the Money Pit's ventilation system. As the pumps start up, Rick is confident the swamp may hold the key to solving the mystery that has consumed treasure hunters for over two hundred years.
