“Yes . . .” I began. “But it won’t do much good if you can’t see what you’re looking for. I wish I could climb it . . . but I think it’s a bit beyond my abilities.”

“Can we both be invisible?” he asked. “You stand at the bottom and spot me. Tell me where to go.”

Ms. Terwilliger turned Eddie invisible, and I then cast the same spell on myself. It wasn’t a particularly strong invisibility spell, and anyone looking for us would be able to detect us. We didn’t want to cast a stronger spell, in case we had to defend ourselves later, and we were taking it on faith no tourist or ranger was expecting to find someone climbing the ruin walls.

Unseen, Eddie and I easily hopped the fence and approached the tower in question. Up close, I now had a better sense for what the golden object was. “It looks like a brick,” I told him.

He followed my gaze, still unable to see what I saw. “I’ll take your word for it.”

The tower’s surface was rough and irregular, with erratic handholds and other openings left behind for long-gone windows. I wouldn’t have been able to climb it, but Eddie managed it deftly, the strong muscles in his body working as he grappled for places to rest feet and hands as he slowly made his way up. When he arrived at the top window, he at least had a place to rest and stand on the opening’s edge. Reaching up, he placed his hand on a brick at random. “Now what?”

“It’s three bricks to your left and two up,” I called.

He counted and moved his hand, setting it on what I saw as a golden brick. “Is this it? It’s loose. I can pull it out.”

“That’s the one.”

I tensed as he pried the brick from the wall. I sensed no obvious traps from this distance, but for all I knew the entire structure would crumble down around us when he removed it. With a little wriggling, it came free. Both Eddie and I froze, waiting for a deadly fotiana swarm or some other disaster. When nothing happened, he tossed the brick to the ground beside me and began scaling his way down. Once he was safely back, we hurried out of the enclosed area and took the brick to Ms. Terwilliger.