Deep in the heart of the Crescent Mine, Patrick and Kristen investigate the strange residue on the back wall of the "ballroom," an unusual, cavernous dead-end chamber. Visible only in black light, the residue has actually dripped into carvings on the wall, revealing the letters V and I; they speculate that they might represent the Roman numeral for six.
That morning, a new miner joins their team: Fast Eddie's son, Mikey. Mikey pairs up with Bucket to begin digging out the rubble pile from the old cave-in by hand, a known hotspot for paranormal activity. Stan, meanwhile, demonstrates the brass board where each miner must "brass out" when they leave the mine, moving their tag from the "in" side of the board to the "out" side. When Jay goes to brass out before lunch, he remarks that Mikey is still in the mine...just as Mikey walks by and informs him that he's been out for at least twenty minutes. This sends up a red flag to the crew indicating that someone (perhaps the mysterious trespasser of late?) is still inside the mine.
Stan sends in Fast Eddie and Bucket to check out the mine to find out who's hiding there. Their search comes up empty-handed, leaving Jay perplexed and a little bit shaken. Stan takes this information to Kristen and Patrick, who review the IR camera footage throughout the mine. While they don't see anything near Jay, they do notice an odd visual glitch in the camera closest to him. As Jay moves through the mine, the glitch follows him on each different camera. Kristen and Patrick take this opportunity while the crew is at lunch to conduct an investigation in the mine.
They check their cameras throughout the mine and determine the equipment is solid. They both hear someone walking further down the mine. After a few minutes, they spot a miner's headlamp at the far end of the tunnel. As they chase it down, they come to an empty dead end, much to their surprise. An EVP session yields few results beyond some strange K2 and EMF spikes that quickly dissipate.
The next day, mine owner Larry asks if he can borrow some cameras from the investigators to set up around the site, to see if he can get this trespasser on film. Patrick and Kristen set up a ring of motion-triggered field cameras around the perimeter of their camp. After setting up the cameras, they head to the county library to see if they can learn more about the strange carvings in the ballroom. There, they discover they may have in fact been letters spelling the word VITRIOL, an acronym found in a Masonic Chamber of Reflection, along with a scythe and hourglass (artifacts already found in that space in the mine). With this new knowledge, they head back to camp.
At the end of the day, Stan notices Mikey and Bucket have not yet brassed out from the mine. When he ventures back to their heading, he discovers they've done very little work for the eight hours they been back there since lunch. Mikey and Bucket are shocked; the claim they've only been back there for a couple of hours. Weirded out by this strange loss of time, Mikey heads to the investigators' shack to explain the situation to them. He shares that in addition to the time loss, he and Bucket both heard knocking in their area. Kristen and Patrick determine that Mikey isn't making this up; he's far too much of a skeptic like his father. They take this opportunity to conduct an investigation.
Patrick sets up a camera aimed at the portal synchronized with the timestamps of a camera facing the cave-in area inside the mine, to track any time loss they might experience. While in the cave-in area, the room is dead, except for one thin column of space that sets their equipment off. As Patrick passes a compass through the zone, it starts spinning around like crazy, indicating a strange magnetic field anomaly. To follow up on Mikey's claims of the knocking, Patrick knocks on the wall three times. After a brief pause, they both hear a loud knock from within the room, with no discernable source.
The following morning, they crew and investigators gather to review the footage. After the crew had thoroughly questioned Mikey and Bucket about their strange encounter (and more importantly, the lack of work done), after reviewing the footage with Kristen and Patrick, agree that clearly something odd is happening in the mines; in the eyes of some of the crew, whether or not it's paranormal remains to be seen.
They break to get started for the day, where Jamol and Fast Eddie see that someone has vandalized their equipment that they'd set up for the day's work the night before. An entire jack-knife drill has gone missing. When Bucket and Mikey arrive at the ballroom to finish their excavation work, they are puzzled as to why someone has left the jack-knife in their heading, with no connecting cables or hoses.
The mystery at the Crescent Mine continues.
Kristen sees the opening in the side of the mountain for herself and makes a startling realization about the way the mine aligns with Baker City.
In this shocking season finale, the miners finally approach the mother lode as Patrick and Kristen reveal the final shocking pieces of the paranormal puzzle.
Stan and Eddie check in with mine owner Larry to outline their prospects for what little remains of the mining season.