Plot summary
Ichabod and Abbie travel to Pennsylvania and take a boat along the Delaware River, transporting themselves to the River Styx using the flag. Meanwhile Pandora, Reynolds, Jenny, and Joe along with Sophia travel to a remote mountain where the Hidden One plans to use the hourglass to regain his full power. To slow him down, they work to sabotage the ley lines surrounding the mountain. Along the way, Ichabod and Abbie discover the remains of an expedition led by Washington and Betsy to secure a portal to the catacombs, which they enter. Inside, they find Betsy, who has been effectively frozen in time. The Hidden One uses his power to turn Joe back into a wendigo, and Jenny is forced to kill him. Having regained all of his power, the Hidden One prepares to destroy the world so he can remake it in his image.
Credits
Adapted from Wikipedia contributors, Sleepy Hollow season 3. HTML formatting and reference markers removed.