As the second mining season at the Crescent draws to a close, paranormal investigators Kristen and Patrick have more questions than answers as they try to put together the pieces of a very complex paranormal puzzle that seems to surround the entire town of Sumpter. They have the possible spirits of Chinese miners, shadow figures, an unknown entity guarding the gold, secret Masonic connections… and at the hub of it all lies the Crescent Mine.
The miners blast through their last obstacle beyond the cave-in. Stan, Eddie and the investigators head in to see what's beyond the blast. The pairs separate, as the investigators detect a constant stream of readings on all their equipment. Meanwhile, Stan and Eddie discover a man-made stone bulkhead wall; Patrick's K2 meter spikes when placed near the wall. He also notices a distinctive Masonic symbol carved into the stone.
After a few minutes, they begin hearing noise all around them, some of them from beyond the wall, itself. Eddie, focused on nothing but their payout at this point, takes out a tool and chisels at the wall to see if they can make their way beyond the stone bulkhead. He manages to loosen a rock; the resulting hole flood the chamber with an overwhelmingly foul stench. Just then, Eddie cries out in pain, stripping off his jacket and lifting up his shirt. The rest are shocked to see Eddie's side covered in a bright red rash resembling a burn mark.
This raises too many red flags for Patrick and he pleads with Stan that they need to leave. Eddie, visibly shaken and unable to explain the experience, agrees. At the campfire that night, Stan fills in the mining crew on what they discovered beyond the blast. When Stan mentions that something happened to Eddie, Eddie refuses to speak up about it. They decide to blast through the bulkhead in the morning. Patrick and Kristen take the opportunity to conduct an investigation of the bulkhead and tunnel leading up to it that night.
While conducting an EVP session, the equipment begins to pick up readings as if in response to their questions, including the sound of falling timber. They continue their EVP session at the bulkhead and begin to hear strange, disturbing growling sounds from beyond the hole that Eddie made into the corner of the wall. The growls grow in intensity, causing everything around them to vibrate. The investigators quickly retreat.
The next morning, Kristen and Patrick meet with the miners to discuss their findings and review the evidence they've collected; evidence that seems to have strengthened the deeper they go into the mountain. Patrick reveals that the Masonic symbol on the bulkhead correlates to the world of evil while Kristen elaborates that the Masons were trying to keep people out of the Crescent, because of the markings on all the portals and bulkheads throughout the mine. They weren't just indicators of gold, but rather warnings to stay away from whatever else lies within.
Kristen shares that they believe there are three types of hauntings happening in the mine, all influenced by the high density of quartz within the mountain: Residual haunts (like a recording of the past playing over and over), intelligent haunts (trying to communicate with the miners, messing with their equipment), and the most troubling, inhuman haunts. Patrick and Kristen are convinced that whatever attacked Eddie from beyond the stone bulkhead is evidence of an inhuman or demonic presence within the mine.
With all the evidence presented, the investigators believe the mine is no longer safe but leave the decision to the miners about whether or not to blast the bulkhead. After a brief discussion, Stan puts their next move to a vote. In an even vote, Stan makes the tiebreaking decision to forge ahead with their plans. The investigators are disappointed to see on their monitors that the crew has headed back into the mine. They grab their gear and head in after them.
Stan, Eddie and Bucket arrive at the bulkhead, quickly followed by Patrick and Kristen who again plead their case. They begin to hear a voice followed by that same low growl from the hole in the bulkhead wall. The growl gets louder as Bucket approaches the hole. Suddenly, small rocks begin falling within the tight space. Stan is immediately on red alert as he recognizes the signs of an impending cave in. He tells everyone to run out of the mine as fast as they can.
They hightail it out of the mine as timber and rock begin to come down around them, grabbing Jay on their way out. Seconds after they cross the portal back out onto the site, the entire mountainside collapses over the portal, completely burying the mine. After a quick headcount, they all realize they've just barely made it out alive. With such extensive damage, the Crescent Mine is done - permanently.
As the group wraps up a challenging mining season, they erect a small monument honoring the lives lost in at the Crescent Mine, in an attempt to appease whatever spirits may remain on the mountain, whose secrets will forever remain buried in the rubble.
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.