After the deaths of Henry and Katrina, Ichabod goes to find himself while Abbie joins the FBI. However, the discovery of an ancient tablet brings Ichabod back to the U.S. and the Witnesses discover that the Second Tribulation may be starting.
When Pandora uses her powers to unleash a new form of evil, Abbie and Crane are forced to face their pasts in unexpected ways.
Pandora resurrects an ancient evil from Ichabod's past to terrorize Sleepy Hollow. Meanwhile, Jenny takes Joe along to track down the Shard's thief, and Daniel offers to clear the air with Abbie.
Pandora summons a new monster to terrorize Sleepy Hollow: the Abyzou, which steals the souls of children who are losing their teeth. Meanwhile, Abbie tells Jenn that she has found their father, and Ichabod goes to the dentist.
Pandora resurrects Ichabod's nemesis General Howe to lead an army of undead warriors on Sleepy Hollow. To stop Howe, the Witnesses need to find his tomb and turn to Brennan and Booth for help.
Pandora unleashes a monster that triggers waves of paranoia in its victims, followed by death. While Ichabod and Abbie hunt it down, Joe meets with Atticus to find out more about his father.
Daniel leaves Abbie in charge while he goes to DC on the Nevins case. Meanwhile, Atticus summons three berserkers to recover the energy from the Shard of Anubis, and Ichabod, Abbie, and Joe close ranks to protect Abbie's sister.
Pandora nurses the Hidden One back to health, but he requires the Eye to regain his energies... and the Eye rests within Jenny. Meanwhile, Abbie resigns from the FBI so that she's free to go after the Witnesses' enemies with Joe and Ichabod.
Ichabod is obsessed with finding his missing partner Abbie. Meanwhile, Joe and Jenny look for a map that can lead them to Pandora, and Sophia receives her first taste of the supernatural when she helps Ichabod battle a Japanese vengeance demon.
While Ichabod quests on the astral plane to find the missing Abbie, Sophie comes to Joe and Jenny and asks for their help dealing with a living Gargoyle that has already killed one man.
As Abbie re-acclimates to a normal life after returning from Purgatory, Daniel calls her in to investigate a series of grisly murders. She and Ichabod realize that the murders are due to a mistake that they met in the past. Meanwhile, Pandora contemplates the loss of her powers.
Atticus Nevins returns to Sleepy Hollow and the group easily captures him. He explains that he unearthed a Ghoul during his time in Iraq--with August Corbin--and the group needs him to stop the creature. However, things aren't entirely as they seem. Meanwhile, Jenny meets with Ezra while Abbie contiues to cope with her time in Purgatory.
While Ichabod and Abbie deal with a creature from Ichabod's past with ties to the Hidden One, Joe realizes that he's overstepped his boundaries with Jenny.
While Abbie and Sophie try to deal with a 400-year-old monster while on an FBI field exercise, Ichabod investigates the symbol while Joe and Jenny try to recover a fragment of Pandora's Box at auction.
The Hidden One attacks Ichabod in the archive... and traps them both when the Emblem activates. Abbie is forced to ally with Pandora to remove the mystic barrier before it's too late, but the price Pandora demands may be too high.
Pandora betrays the Hidden One when she realizes that he will never consider her as an equal, and makes her stand with humanity. Meanwhile, Ichabod and Abbie realize that the Founding Fathers' flag--the one that Betsy created--holds the key to returning to the Catacombs and seek it out... putting a deadly guardian on their trail.
As Pandora and Daniel join the team to stop the Hidden One from destroying the world, Ichabod and Abbie find their way into Purgatory and make their way to the Catacombs. There they find an unexpected ally from Ichabod's past.
After escaping the Catacombs with the reassembled Box, Abbie and Ichabod free Pandora to help them defeat the Hidden One. However, the cure may prove worse than the disease, and Ichabod calls upon a former opponent for help.
