Plot summary
The Hidden One reacts angrily to the news Pandora knew that Abbie and Ichabod had the emblem in their possession and strips her of most of her power. Pandora turns against him and visits the Witnesses, offering to help them recreate her box and imprison the Hidden One within it. Although skeptical, Ichabod listens on as she tells him it can only be regenerated in the catacombs where it was first forged. While searching for a golden thread left by Betsy Ross in the first American flag, they accidentally summon the immortal guardian who protects it.
Using a musical clue, they find the entrance at Fort McHenry. Pandora appears before the Hidden One in astral form and escapes with him. Ichabod and Abbie discover Betsy's flag hidden inside a statue of Orpheus, with Joe and Jenny arriving to defeat the guardian. The dawn's early light reacts with the flag, revealing a path left by Washington leading to the catacombs.
Credits
Adapted from Wikipedia contributors, Sleepy Hollow season 3. HTML formatting and reference markers removed.