|The Precocious Apprentice|
Use the teleportal to follow Hallie, and protect her at all costs.
You're too late. Demons have already broken the ephemeral guardian and hidden it away. Hallie's inside. If you don;t want to see her gutter, you'd better get in there to help her.
Go to the Alter or Vadoma and use the teleportal to join her. Keep her safe and try to restore the guardian's seal. There's not much time.
Once you enter the Eldritch Academy Grounds walk staight ahead and go up the first stairs you see, once you're at the little camp with all the NPCs talk to Ozzi the Teleport Master. It will cost you 20 silver to teleport to the Witch Queen's Catacombs. When you get in there, head downstairs to the Hall of Vadoma and that is where you'll find the Altar of Vadoma teleportal.