"Dark Mirror" is the thirteenth episode of Season Three of Fox's Sleepy Hollow. It was written by Sam Chalsen & Nelson Greaves and directed by Sylvain White. It is the forty-fourth episode of the series overall, and debuted on March 4, 2016.
As a monster resembling the fabled New Jersey Devil ravages Sleepy Hollow, Crane must draw on his past to find the connection. Meanwhile, Jenny and Joe stumble as they navigate their new relationship and Abbie continues to struggle with the aftermath of her trauma.
A jogger, films himself and his fellow runner Alice running through the woods. Suddenly something grabs Alice and hauls her into the woods. The jogger runs over and finds Alice's bloody corpse on the ground... and then something attacks him. Once it's done, the Hidden One arrives and reminds the creature that he is its master. The creature kneels before him and begs forgiveness.
Abbie is jogging and remembers her time in the Catacombs. She returns home and goes to her garage, and unveils the symbol on the wall.
In the house, Ichabod, Joe, and Jenny make Sunday brunch. Ichabod complains about how the food is named, and Jenny realizes something else is going on. He shows the others his rejection of citizenship from Immigration. He failed because he missed his interview when he was looking for the missing Abbie. Jenny says that they'll use Joe's money to hire Ichabod a lawyer to plead his case, and goes to make mimosas. She goes to the garage to get champagne and sees the cloth on the wall. Abbie interrupts her, holding her the bottle of champagne, and gets Jenny inside.
The group finishes breakfast and Ichabod and Jenny take the dishes to the kitchen. Ichabod feels better and points out that Abbie has cheered up recently after her time in the Catacombs. However, they both figure that Abbie his hiding something. They agree to keep an eye on Abbie without pushing her. The FBI calls Abbie and tells her about a possible serial killing of two antiquarian professors.
Abbie and Ichabod check out the crime scene. The wounds are too precise for an animal attack, and there is evidence of poison. Ichabod suggests that the wounds are a mixture of snake, wolf, and scorpion, but Abbie notes that the blood splatter indicates one attacker. Considering, Ichabod says that there were rumors of an animal in the Jersey woods: the Jersey Devil.
Joe and Jenny drive back to Jenny's trailer, and find the floor flooded. The waiter main hookup has cracked and Jenny shuts off the valve. Joe figures that she'll need a whole new system, and points out that the entire trailer could use an innovation. He's more than glad to spend some of his money to do the work for their future together.
At the archive, Ichabod checks the references to the Jersey Devil dating back to 1777. There are a dozen unexplained deaths in the Jersey woods in the last ten months, and the last two were the runners in Atlantic County Park. Ichabod remembers the place and checks his maps, and tells Abbie that he met Benjamin's rival scientist Japheth Leeds there.
Ichabod is writing in the woods when Leeds approaches Ichabod and asks if he intends to be another of Benjamin's whipping boys. Leeds insists that Benjamin is no rival because of his lack of skill, and tells Ichabod to pass on his message that he'll bring Benjamin if he keeps demeaning his work. Ichabod wonders why Leeds' Electrostatic Inducer is superior to Benjamin's lightning, and Leeds merely tells him that he chose the wrong mentor.
Among Leeds work was isolating animal traits and using them to augment humanity: genetic manipulation. He finds Benjamin's comments about Leeds in his Almanac, and finds a coded message. Benjamin says that Leeds had turned to alchemy and ancient magic, turning his back on the scientific community. Leeds experimented on himself, altering his body.
Leeds drinks his formula and screams in pain, and then mutates into the creature that will be known as the Jersey Devil.
Ichabod and Abbie realize that Leeds is still alive over 200 years later, and head to Atlantic County Park. En route, Jenny calls them to say that the two murdered professors had a Mayan prayer mask and a Celtic plate on loan. Both plates were solid gold and known to be the vessels of the gods. She heads back to her trailer to find the reference back.
At the park, Ichabod and Abbie find the ruins of Leeds' lab and fid an old stove marked with alchemical markings. He finds a hidden switch and the entire platform moves aside to reveal a passage downward. They descend and the gaslights activate automatically, revealing Leeds' lab. The Witnesses look around and find notes with references to the Hidden One. Ichabod realizes that Leeds was a worshipper of the Hidden One, and came in service to his master. Abbie finds a necklace in the shape of the temple symbol, and Ichabod comes over to look at it. He doesn't know what it means but figures that it represents evil if Leeds had it.
Jenny drives back to her trailer and discovers that Joe has bought her a new trailer. He comes out with a giant red bow and admits that she wasn't supposed to be back yet. Jenny is furious that he replaced her bed without asking, and Joe assures her that all of her stuff is in either the Masonic Cell or a storage unit. She gets in the truck, tells Joe to get in, and heads to the Cell.
Ichabod finds Leeds' research and notices that Abbie is staring at the symbol. She's also found a wax cylinder from a phonograph, and Ichabod plays it on Leeds' device. It's a movie projector, and Leeds has recorded information on the Hidden One. He documents how the gods of the ancient era ruled over humanity, and Pandora was one of the servants.
The Hidden One is outcast and condemned to live in the Catacombs, and Pandora brings the offering to him. She once offered him a flower to bring him a bit of joy, and the Hidden One eventually tells her that he stands guard over all of the evil in the world, hidden in a Box. He summons the Box and shows it to Pandora, and explains that the evil within the Box is filtered through his brother's golden hourglass... and the evil is the only thing that can destroy his brother. Pandora and her brethren unleash the Box's contents. However, humanity betrayed the Hidden One and locked him away forever.
Ichabod realizes that the gold of the stolen artifacts is the key, and Abbie figures that Leeds plans to recreate the Golden Hourglass. The two relics are pieces of it, and the Hidden One plans to use the power of the monsters he summons using the Hourglass. The transformed Leeds comes in and recognizes Ichabod, and Ichabod says that Benjamin knew Leeds' true nature as an abomination. The Jersey Devil pours himself a drink and insists that his god is bent on restoring power to the worthy. He describes a golden age where geniuses are recognized.
The Jersey Devil lashes out at Abbie, and the Witnesses open fire on him. He's immune to their bullets, but Ichabod manages to stab him in the back with his own scorpion, even though he scratches himself on the stinger. However, the Jersey Devil recovers and knocks Abbie unconscious. Ichabod collapses from the venom and the Jersey Devil picks up a technology-laden staff and walks out.
Abbie wakes up and has the dying Ichabod tell her what she needs to make an antidote. She does so just in time and Abbie prepares it. However, she freezes as she sees the symbol again. Ichabod whispers her name, and after a moment Abbie finishes her job and gives Ichabod the antidote. As she waits for Ichabod to wake up, Abbie grabs the symbol. Ichabod finally overcomes the poison and Abbie apologizes for being distracted. He realizes that the symbol captured her attention and she has it. Ichabod warns that it's evil, but Abbie says that she's needed it for months. She saw it on the temple wall and it gave her peace, and still does. Ichabod says that soldiers returning from the war do what they need to carry on.
Ichabod mixes an explosive to blast open the door. Jenny calls from the Cell and reads Abbie a legend about an hourglass artifact that bestows omnipotence on the user. The key ingredient is the Fire of the Gods, which will transform the relics into the Sands of Life. Abbie tells Ichabod what Jenny has discovered, and Ichabod realizes that the staff the Devil took is his Electrostatic Inducer. They figure he's going to the highest point in the area and Ichabod says that he knows where it is.
The Hidden One watches in his scrying well as the Devil begins the ritual. He places the Inducer in the bowl... and Ichabod and Abbie arrive. Ichabod warns that the Hidden One cannot be trusted, and the Devil says that he chooses him as his master. He activates the Inducer and lightning strikes it, melting down the stolen relics. They melt and transform into the Sands of Life, and Abbie opens fire without effect. Ichabod dismisses the display as parlor tricks, and Abbie slips around the side as Ichabod says that the Hidden One shall betray him. Abbie grabs the inducer and drives it into the Devil's chest, the lightning stabs down, hitting the Inducer and disintegrating the Devil. However, the Sands of Life are gone.
Joe brings the trailer back and assures her that it's all the way it was. He admits that he jumped the gun but insists that his heart was in the right place. Jenny points out that he stole her home, and says that it's about boundaries. They kiss and Jenny tells Joe to never touch his staff again without asking. She then goes inside and locks Joe out.
At home, Abbie sits and fingers the symbol. Ichabod returns and tries to slip by her, and Abbie asks him to talk to her. He says that he understands what she's going through, and it's not his place to judge. Abbie points out that Ichabod almost died because she needed the symbol, and she thought all along that he could control her impulse. She realizes that she was lying to herself, and gives the symbol to Ichabod. She stares at it and says that she needs his help.
At the cave, the Hidden One gives the same flower to Pandora, and says that she is the only gift that he ever needed. He then asks Pandora to join him and offers his hand, and Pandora takes it. They go to the scrying well together and the Golden Hourglass floats out of the water. The Hidden One takes it and the Sands of Life flow down into it. Turning it over, the Hidden One says that the time has come and the new world has arrived.
- While preparing their breakfast Crane complains that "...these eggs are named after a traitor...". Presumably he is preparing Eggs Benedict and is referring to Revolutionary War traitor Benedict Arnold. However eggs benedict are not named after Benedict Arnold but Lemuel Benedict, a New York banker who in 1894 ordered his favourite foods for breakfast when staying at the Waldorf Hotel and suffering from a hangover.
- The monster in question is a replica of the NJ Devil, not the actual urban legend. Japheth Leeds was never born from Mother Leeds, but rather an inventor and Ben Franklin's rival who mutated himself. It is, however, possible that he could belong to the Leeds' family.
- Japhet Leeds was the husband of Deborah Leeds the woman who may have been the historical basis for "Mother Leeds" the woman who gave birth to the Jersey Devil in the folk story.