Plot summary
Ichabod experiences a prophetic dream where he's at the Archives, and encounters a young girl whom he describes as no more than ten or eleven years of age. When he awakens, he travels to The Vault to learn more about his dream. Malcolm Dreyfuss meets with the Dyer sisters, a coven of immortal witches, to exchange the dagger of Z'urn D'oragh for the Witches Stone. Malcolm reveals that Moll, the coven's leader, has lied to the others, who kill her in revenge before escaping into the city. Ichabod and Diana investigate Moll's death, and Ichabod tells Diana that the coven helped Washington expose John André, for which he rewarded them with a plot of land.
Ichabod recognizes the picture of Molly on Diana's phone as the girl from his dream and tasks Jenny with investigating her. At Molly's school, Jenny steps in and stops two girls from bullying Molly before Ichabod and Diana arrive. Molly breaks her silence by greeting Ichabod. They track the Dyer sisters to their sanctum and discover an "infernal machine" that maintains their immortality, which Ichabod destroys. Ichabod and Jenny decide not to tell Diana that Molly is the next Witness.
Credits
Adapted from Wikipedia contributors, Sleepy Hollow season 4. HTML formatting and reference markers removed.