The Back Door is a teleportation mechanism, invented by Jenkins, which is located in the Annex. A mini version was created with a limited charge for The Librarians to escape The Bermuda Triangle, however instead they were used by The Librarians to get people off a crashing plane. Flynn went through The Bermuda Triangle alone and escaped by other means.
- There must be a door near to where the user wants to be;
- The destination must not be jiggling or moving very rapidly; 
- The door is able to track people instead of places , although:
- The portals would not be stable, and could disappear at any moment;
- The user needs to attach an object that is loved by that person to one end of the Door;
- The person would need to have another cherished object near him or her;
- If the person leaves said object behind, the Door will teleport the user to the object, not to the target.
- The door has the side effect of scrambling Flynn's senses. 
- The Back Door is, when not in use, a regular wardrobe.
- The Door is able to teleport to the Loom of Fate with the help of certain powerful objects, such as:
- When combined with the items above, it can also be used to reattach the Anchor Chain.
- The back door can be keyed to the most powerful source of local magic sending the Librarians directly to that location.