The whole band is back together for more mystery hunting, and they're not wasting any time getting to the good stuff: Jael, Jack, Devin and Dana meet in Florida to investigate Fort Jefferson, a ruined Civil War stronghold for the Union. It lies 80 miles off the Florida coast on Dry Tortugas Island, so the only way to get there is a day-long boat ride. Once they arrive, there's no going back, and there won't be anyone else there...or will there?
Before they leave, they speak with a witness, Tortuga Jack, who tells them of the poltergeist activity there. Afterwards, expert David Sloane fills them in on the history of the place as a prison for murderers and Union deserters. Among the infamous prisoners was one Dr. Samuel Mud, who treated John Wilkes Booth. Tortuga Jack said he was pushed in Dr. Mud's cell - not grazed, but pushed - by a non-physical entity.
The team arrive with some daylight to burn, so Jael and Dana scout the water while the boys scout the land. When they meet up again, Jael shows off her awesome find - a rusty chain that was surely used to bind a prisoner to the floor of a cell. As night falls, Jack and Jael head out in a rowboat to see if they can find any of the ghost lights rumored to be there. Jael goes underwater while Jack keeps an eye on the surface, and he sees a strange light from the shore. It's not Devin and Dana, so he gets Jael's attention and they rendezvous with the other pair, who have just had their own freaky experience. A brick fell at Dana's feet, and Devin sees a red mist float through the viewfinder of his FLIR camera. He also sees a mysterious light - could it be the same one Jack saw? - emanating from the lighthouse. As Devin looks closer, he sees the shutters of the lighthouse window close of their own accord.
The next day, Jael wakes to see their boat floating out to sea. She rouses Devin just in time for him to dive in the water and bring the boat back to shore. A few minutes later, and they'd have been stranded! They regroup in time for a Skype call with two witnesses: Alicia, who says she heard a loud moan followed by her headlamp turning on of its own accord, and Larry Stanford, who was physically poked in the side as he heard someone shout, "Hey!"
They begin the investigation for the second night with remote control vehicles - the boys blasting "The Battle Hymn of the Republic" from an RC car, and the girls taking an aerial view of the fortress with the RC chopper's camera. The boys find the RC car has found itself in Dr. Mud's cell. Nearby, they hear whispers and decide to put the motion capture device - a light-emitting grid that picks up any object - in the hotspot. Meanwhile, the girls spy a dark spot near the lighthouse and decide to take a closer look. They find themselves in the lighthouse, and when Dana goes up a ladder into a small chamber, the door in the floor slams behind her. Jael can't open the door by herself and calls for help. The boys come running and are able to open the door immediately, but not because of a huge difference in strength - rather because it felt like something was sitting on the door and holding it down.
Jack decides they need to do an EVP, and when Jael drags the chain she found across the floor, they all hear a strange rapping. Jael picks up a heat signature on the IR camera that looks amazingly like a full-body apparition. She follows the form and the group wind up at a grave site of a man who died in 1862. The team decide they have a ton of footage, and they need to start reviewing it soon. They get a good night's rest and the next day discover that their experiences are backed up by their recordings. Jack decides that there is some definite paranormal activity at Fort Jefferson on Dry Tortugas Island.
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.