Percy mostly kept his legs under him for the rest of the trip out from the main building and to the three story structure. He was rather grateful when they didn't have to take any stairs to the red door marked "Old World". He reached for the handle, but though it moved, the door wouldn't open.

Remembering the paper sleeve, he took it out and waved it at the door, then pressed it against the wood. Nothing. "What's the trick?"