After stepping through the gate, you find yourself in a place that doesn't look like a cave at all.
It's a library, and a huge one. You are alone in a wide gallery with polished marble floor, going straight ahead as far as the eye can see. Actually, when you look around the gate is not there anymore, only more of the corridor. High bookshelves reaching to the roof line up at both sides, with secondary corridors between them. The books themselves are different. They have no titles printed on them, just names, and each one is a different color and size.
Only a faint light illuminates the place, coming from nowhere in particular, and the silence is so complete that you can your heartbeat.
Before you can do anything you hear a deep, severe voice that echoes through the ambient.
"This court is now in section. Before you proceed, be warned that no lies are allowed. Answer true and answer right, or your sentence will only come faster."
With that warning the voice fades, leaving you again alone in the endless gallery.