Jamol's first turn on the mucker ends disastrously as it mysteriously catches fire, putting his life in peril. Thanks to quick thinking by Dingus, Jamol makes it out of the mine alive, but visibly shaken. The crew presses on for the night, understandably without Jamol. They take the next day off to regroup after the fire; Stan calls an end to the night shift after the previous night's harrowing events.
At their base camp in Hell's Canyon along the Snake River, Kristen and Patrick await their boat ride back up the river. Patrick has recovered from the previous night's strange paranormal occurrence that left him incapacitated, but is reluctant to talk about it in the morning. Kristen wonders just how far they're willing to go when it comes to discovering the secrets of the Crescent Mine.
When the investigators return to camp, they're shocked at the number of events that took place while they were gone. More mysterious equipment malfunctions continue in the mine, as they discover the water tank that supplies the water pressure for the jack-knife has been completely emptied.
Kristen and Patrick suspect that something is trying to manifest itself in the mine and has been draining the miners' equipment as a result. Patrick proposes using a new investigative tool to help alleviate some of the paranormal activity in the mine: A Tesla coil. A Tesla coil generates extremely high voltage with the flick of a switch; the theory is that whatever is trying to manifest itself can take energy from the coil instead of the miners' equipment.
The mine is emptied and the Tesla coil set up. Within a few minutes of it being turned on, they begin to see strange visual anomalies on their surveillance system in the mine. They shut it down and remove the coil from the mine and head in to investigate. All of the high electric charges left in the air render their EMF and K2 meters untrustworthy; instead, they focus their investigations on EVP work.
Within just a few minutes, they hear the sounds of miners working and hammering in the mine, despite being the only people in there. They chase the noises throughout the mine, but find no one. At one point, in response to their questions, they hear a low, menacing growl, similar to the one they heard last season. As they get ready to wrap up their investigation, they hear an overwhelming sound of rushing rock and water - but only the sound passes around them and dissipates, leaving nothing in its wake. The experience has the investigators baffled.
The next day, Kristen and Patrick review their evidence from Hell's Canyon as well as from their Tesla coil experiment. They show the miners footage from right after the Tesla coil was activated and reveal a dark shadow figure, similar to the one they saw following Jay earlier in the season.
Kristen meets with the mayor of Sumpter to learn more about the town's dark past. She learns that eighteen Chinese miners were murdered in the neighboring town of McEwen in a horrific fire. She and Patrick head to the cabin ruins located in McEwen to conduct an investigation.
Back at the mine, they blast out the raise to clear out the muck faster and discover that the raise opens up into another open drift. Jamol is small enough (and greenhorn enough!) to be able to fit up there and take a look. As he climbs up and peeks into the gap, Jamol hears a distinct growling noise that sets him on edge and has him hastily climbing back down. The crew gets the idea to send RIPA up into the space for their own safety.
At the McEwen massacre site, Patrick and Kristen begin an EVP session in English and Cantonese. They begin to hear the sounds of someone walking near them with hits on their K2 meter. As they follow the sounds and hits, the temperature drops rapidly. Suddenly, Kristen is touched - not once, but twice - by an unseen force as their motion detector also goes off. Shortly after, all activity seems to die down; they call it a night.
The next morning, Patrick and Kristen agree to send RIPA into the newly discovered rift. The miners rig a pulley system to lift RIPA, which weighs several hundred pounds, the seventy feet straight up. With Jay stationed at the staging platform, they hoist RIPA up to him. As they just get her settled into place, things start to go haywire as Jay desperately cries for Patrick to cut all power off to RIPA.
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.