Over the bridge
The three of you, plus Paul the spider and Spot the Raven, materialize upon an teleportation circle within a large, dome-shaped stone chamber, at least 30ft in diameter. The only source of light is from a set of torches burning with magically heatless golden fire on either side of a closed set of large, double doors. Centered on the doors is a wooden placard engraved with the words:
"Death meets any who enter these once hallowed halls. Not from spite, or malice, or even preservation, but from the horrors that now roam freely here."
Written in common and copied in sylvan.
Opposite the doors is a large, round-topped tunnel. Everything has the feel of being an indoor road, with this chamber a landing before the gates of a keep. Far down the tunnel you can see the hint of daylight.