Grant Wilson and Jason Hawes excitedly tell the team they are invited to visit Fort Mifflin in Philadelphia. Among the many places recommended by fans, this was towards the top of the list and now that a new section has been recently discovered, they have the chance to be the first team to investigate.
Upon arrival, they meet caretaker Wayne Irby, who shows Grant, Jason and Steve Gonsalves around the fort and tells them of apparitions and other experiences that have been reported. After that, the team sets up their equipment and begin the investigation.
Jason and Grant start in the Officer's Quarters, seeking the spirit of Elizabeth who committed suicide after her daughter's death. As they do their electronic-voice-phenomena (EVP) work, Jason thinks he hears a girl's voice ask for "mommy."
In the blacksmith shop, Steve and Dave Tango also do EVP work but feel a sense of dread. Jason and Grant head down to Casemate 5 and see a hot cot that should be dead cold. While stopping at the latrine, Dave is spooked when he sees a shadowy figure in the doorway to the women's room.
Heading into the newly discovered Casemate 11, Jason and Grant begin looking around. The tight confines begin to affect Jason who is slightly claustrophobic. He thought he saw a figure crouching in the shadows, but could find nothing. Both men hear footsteps nearby, but again the source eludes them.
Jason asks Kris Williams to check out Casemate 11 by herself, as part of her training. They want her to build her confidence as an investigator-in-training. She goes down but immediately feels uncomfortable in the confined space. When the flashlight begins to go "funky" she climbs back up the ladder. Jason consoles her, noting that "when in doubt, get the hell out."
Steve, meanwhile, offers Dave $60 to crawl beneath the commandant's quarters. Despite his dislike of insects in general and spiders in particular, Dave does, but finds nothing paranormal.
Jason and Grant re-enter Casemate 11 and feel the thick air and sense the closeness. They both hear a whisper or breathing, then footsteps and maybe something scratching on the other side of the wall. Grant senses a cold spot and then is shocked when he looks through a window and sees a bearded face on the other side. It was solid with a scraggly beard and blond hair. A second look and the face was gone but Grant is convinced the face was there. Finally, Dave enters Casemate 11 to see for himself, and immediately feels easy as he does EVP work. He gets chills, and not feeling wanted in the space, scrambles up the ladder after 10 minutes.
Over the next few days, Steve, Dave and Kris review the hours of video and audio recordings, sharing their findings with one another. Dave finds something moving on one thermal image while the hot spot on the cot is also very clear. Everyone agrees the audio clip of "mommy" is very clear.
Jason and Grant review the team's work and are surprised to hear "mommy" twice on the tape when they only heard it once. Another sound, from Casemate 11, sounds like "the boss wants it deeper" while another clip captures, "Can I get some water?"
To everyone's surprise, the thermal scan captures a figure down the hall when no footprints were found. There's also warmth captured on the nearby stove.
Jason and Grant meet with Wayne and review how they did their work and what they experienced. Then they play the clips that are considered significant. Wayne confirms that the figure in the tunnel is where prisoner William H. Howe escaped before his recapture and hanging. He also agrees with the audio clips about asking for water and the boss' request. Wayne explains that in 1861 Casemate 11 was refurbished to become solitary confinement and was made deeper. He's absolutely amazed by the thermal images displayed on the monitor. The TAPS team confirms their belief that Fort Mifflin is subject to "residual haunting", that is, the echoes of people who experienced events at the fort have been imprinted and can be experienced today .
The Ghost Hunters cast give a shout out to their fans!
The cast assigns superlatives to their fellow investigators as part of Ghost Hunters 10th anniversary celebration.
The cast shares their scariest moments from the last ten years of Ghost Hunters.