Devin and Jael are in the middle of a cold front, so they figure, time to go to a frigid lake and look for a monster! The Lake Murray Monster, first sighted in the 1930s, is reported to be 40-60 feet long, with a serpentine head and body. Father and son jetskiers reported seeing the beast, and said its scales were as large as a human hand. A local researcher named Shannon Kincaid is wrote a book on the unexplainable and she points out some of the hotspots for monster sighting. She also warns them to be extremely cautious – no one knows, as of yet, how the thing eats, or what it eats.
On a small island that Shannon directed them to, Jael and Devin meet up with two witnesses, one who says he saw a 20 foot hump rise out of the water, then disappear just before his boat was pushed sideways. The other has a blurry picture of what he believes to be the legendary creature, and it's like nothing Jael and Devin have seen before. Both witnesses are truly afraid of whatever it is in the water, and exhort the investigators not to go diving for trouble.
But of course, trouble is their middle name, so when the sun sets, Devin and Jael set up cameras all around their camp as well as on their boat, and begin the hunt. Jael stays on shore monitoring the cameras while Devin takes the thermal imager out on the boat. He sees a warm patch on the thermal just as Jael sees a form move on one of the IR cameras and the depth reader on the boat goes from 20 feet to .9 feet. This is clearly the right time for their night dive, so Devin returns to shore to pick up Jael.
Before submerging, they call Jack, since he's done a similar dive in the past. He has the helpful tip not to kick up silt, given the low visibility of the place. The duo review their hand signals for underwater and dive in. Before long, Devin's suit malfunctions and he has to surface, but he sends an RC submarine into the water. He asks Jael, via walkie, to signal when she sees the sub, and she does. Jael's camera isn't picking up much because of the dark murkiness of the water, but the sub catches a creepy, eel-like visage just before malfunctioning. Jael's air is getting low, but she saw something intriguing and doggedly pursues it. All the while, Devin is panicking on board the ship – he has no way of knowing what Jael is up to until she surfaces, her oxygen tank almost empty.
The following day, they review the footage and, in addition to the image the sub picked up, they see that something struck the boat and rocked it while they were both in the water. They contact an expert in South Carolina to see if he can identify the face on the camera from the sub, and he says it is most definitely a sturgeon. In that area of the country, he says, sturgeon are known to grow as big as nearly 300 pounds.
Jael signs off the case with a profound sense of uncertainty. What they saw was a preternaturally large fish, but the hundreds of other reports from the area could still point to something monstrous.
Jack and Dana, meanwhile, are exploring legends of angry spirits from the Donner Party, the infamous group who were trapped in a mountain pass and had to eat their own dead family members in order to survive. They start with an interview at the Old Jail Museum with a woman named Chelsea, who tells them that the party took an ill-advised shortcut, and that was what cost so many lives. Tamsen Donner was opposed to the shortcut, but the men voted against her. For that reason, it's believed that her spirit is particularly aggrieved, as she had to watch her children die in the freezing cold.
Chelsea introduces Jack and Dana to her friend, Jen, who has had many experiences in the active areas, including seeing a menacing shadow figure, seeing ghostly candle flames, and feeling dozens of eyes on her. She agrees to let her dog, Harlan, go with Jack and Dana, as he's been keenly aware of unusual activity on their nighttime camping trips.
They snowshoe out to the Murphy Cabin site (named after the other family in the party) and se up camp. Jack secures a GoPro camera and light to the dog's back, and he immediately starts barking at something in the shadows. Jack lets Harlan pull him into the woods, where he picks up a shadowy figure on the FLIR, but no sooner does he see it, but it disappears from the screen. Dana rushes to the spot and they set up an EVP with beef jerky as a trigger for the hungry ghosts. Dana sets down an epod, a device designed to change color when movement is detected. As they begin asking questions, Dana feels something sharp on her neck. Lifting up her hair, Jack sees a huge red scratch across her skin. The epod lights up and Dana begins to feel intense stomach pains. She moves a little way off and succumbs to the nausea.
Jack returns to camp to monitor the IR cameras while Dana continues with the EVP. Harlan begins barking again, and the cameras on Dana, as well as two others, blink out. Jack has no read on where Dana is, so he sends his RC copter, outfitted with a heat-reading camera, up to find her. He sees her, but he also sees a humanoid form mere feet from her. He goes to bring her back to camp, and as they walk back, they see ghost lights blink on, then off. They look like they came from Murphy Cabin, but they don't see anything there. Dana gets the unsettling feeling that they're being watched.
As they review the footage the next day, they note that the shadow figure from the thermal camera could be a malfunction due to the extreme cold, but they catch a disturbing audio clip from the EVP that sounds like clicking teeth in response to Dana's question, "Is it easier to communicate through me?"
Although some of their evidence is shaky, taken all together, the pair of researchers have to say that something mysterious is certainly at play near Donner Pass.
The pirate Heracleo betrays team Spartacus, Caesar stabs Spartacus, Agron does an amazing spin down a rope, and Crixus and Naevia return to fight for the city. A real action packed sequence.
Caesar: spreading news and making everyone hate each other. When Crixus gets wind of his tale, he confronts Agron head-on.
Count all of this episode's zombie kills along with us.