Piper has enrolled Wyatt in a preschool, but he is unwilling to play with the other children. As Piper speaks of her worries with Phoebe and Paige, Wyatt orbs back to the manor. The sisters orb after him and find that a door has appeared next to the manor's stairs. The door opens and a man calls for help; the Headless Horseman appears behind him and chops off his head. His head can still speak.
The head says his name is Sigmund and explains that the rest of him at Magic School. He says Gideon needs help. Leo orbs in and Sigmund recognizes him. Leo says that Magic School is supposed to be protected from evil.The sisters and Leo go through the door, with Sigmund's head with them. Leo says that Gideon was his mentor and had advocated his and Piper's marriage before the rest of the Elders. The sisters, Leo and Sigmund's head meet with Gideon, who says the students had been pulling pranks and finally one conjured the Headless Horseman, who is cutting off teachers' heads. He believes the guilty student is influenced by a demon. Gideon tells the sisters that they can find what they are looking for on the grounds of Magic School.
Paige takes over one of Sigmund's classes and find one of the students levitating another against his will. She finds her new students to be very disrespectful. She suspects that one of her students conjured the Headless Horseman.
Phoebe follows a wolf, which leads her to a campfire. The wolf morphs into a Shaman, a woman who notes that Phoebe's premonitions are unreliable lately and offers to help her see her future more clearly. She tells Phoebe she is conflicted, questioning her future; Phoebe uses her empathic power, but cannot tell if the Shaman is telling the truth.
Piper and Leo are watching Wyatt, who is being much more sociable here than at the non-magical preschool. A mother comes in and describes her near-miss with the Headless Horseman. An alarm sounds, and the Headless Horseman appears and cuts off Piper's head.
Leo and Paige walk into the nursery and find Chris there with a demon using some kind of power on Wyatt. Chris claims that he can explain, but an angry Leo orders him out. Leo orbs Wyatt "up there."
The Shaman offers Phoebe a potion, which she drinks. She has a vision of herself before a portal and beset by demons. On awakening, she finds herself fighting demons. Paige orbs in and tells Phoebe what happened to Piper, but Phoebe decides to stay to seek answers.
Paige orders her students out the door and into the manor. She says that one of them is responsible for the Headless Horseman. The students argue among themselves. The door opens and the Horseman rides out. It cuts off no one's head, but runs out the conservatory door. Gideon offers to help Paige find the Horseman; no one outside would be protected and would be killed if beheaded. They find him and Gideon opens a door, returning the Horseman to Magic School, but a mortal killer has been killed.
Chris claims that the demon was able to scan for evil and could possibly find out who was going to turn Wyatt. Gideon says that he had promised that Magic School would never cause harm and that he now must close it. Paige talks him into changing his mind. The students in the manor suddenly freeze and an unseen figure grabs Piper's head. Paige and Gideon conclude that one of the students did this and is not actually frozen.
Phoebe has tried her vision quest again, without much success. The Shaman advises her not to use her powers to get through, but to "want it more than anything". She takes another potion, but this time, the demons pass through her without harm and she reaches the portal. On the other side, she sees Wyatt at about six years old and he has a brother; Phoebe then notices that she is pregnant when Paige, Headmistress of Magic School, needs to pawn off taking her to a docotor appointment on Piper. Wyatt's brother asks for Phoebe's help and it morphs into Chris asking for her help in the present. The Shaman encourages her to embrace her powers and her path.
Back at the manor, Phoebe uses her empathic power to examine the students and finds Zachary to be angry, and to be astral projecting. His projection fades, and the sisters and Gideon realize that he's tapping into other people's powers. He had frozen the room with Piper's power.
Inside Magic School, the Horseman attacks again, and cuts off the heads of Paige and Phoebe.
In the manor, "Paige" comes out of the door and urges Leo to orb the other students away. Once Gideon is alone, "Paige" morphs into Zachary and attacks Gideon. Zachary feels that he's being held at magic school against his will and being kept from his family and friends.
The Charmed Ones' heads say a spell and vanquish the Horseman. When he explodes, the sisters are made whole again. They convince Zachary to let Gideon go by explaining the similarieties of their having to deal with magic in their lives and his.
Zachary is back with his family at the end of the episode. Paige is contemplating binding Richard's powers. Phoebe talks vaguely about what she saw on her vision quest. Phoebe asks Chris if he is Wyatt's brother. He says he will be, if Piper and Leo get back together soon enough.