Down the hole!
The last building was empty. Our gaze turned to the well in the center of the courtyard.
I shifted to a spider form to explore. Things were quiet. No obvious traps were present. Really, no obvious anything was present. I headed down to investigate the bottom of the well, perhaps right below the waterline was a tunnel or something.
I didn't make it all the way to the bottom before I felt an odd breeze. Investigating a bit further it turns out there was a well made secret door. I informed the others and we attempted our breach.
As only one person could pass at a time it was rough going until we got a sufficient foot hold. I attempted to swing swing wide and get in ahead of the blockage, but only managed to bruise my side pretty bad. In the end we overcame the initial resistance. Echoes rumbled out of the depths of the cavern hinting at the expanse we've uncovered.