“No,” I said firmly, feeling more and more confident of my suspicions. “She’s not going to turn us in. Unless you see active signs of someone coming after us, we’re pushing on to Ha Ha Tonka.”

I was reeling as the drive continued, still in awe at this new revelation that Zoe might be having doubts—if not about the Alchemists, then at least about what had been done to me. Once I recovered from my initial shock, I found myself feeling an emotion I hadn’t felt about her in a very long time: hope.

Clouds were thinning out when we reached Ha Ha Tonka State Park, and the early morning temperatures were already promising a sweltering day ahead. We parked and stopped by the visitors’ center, clustering around a map of the park. Although there were extensive grounds and trails, we decided the ruins of the massive stone building—which even the park referred to as the “castle”—were the place to start, seeing as that’s what our clue directly connected to.

No one else was out this early, aside from the staff at the visitors’ center. Ms. Terwilliger and I walked around the stone ruins, looking for signs of magic and occasionally casting detection spells. Eddie stayed near us protectively, doing his own searching as well, but mostly relying on us to find whatever it was we were looking for. The part of me that had long loved art and architecture couldn’t help but get caught up in the ruined grandeur around us, and I wished Adrian was with me. We hadn’t officially had a honeymoon after our wedding, but we’d often talked about all the potential places we’d like to go, if only we had the freedom. Italy was still high on my list, as was Greece. But honestly, I would’ve gladly settled for Missouri, if only Adrian could be with me, free from pursuit.

After a few hours of searching, we were hot and sweaty but had yielded no results. Eddie, still not convinced of Zoe’s intentions, was growing nervous about us lingering and wanted to be on the road soon. As lunchtime neared and we contemplated calling a break, something flashed in my periphery. I turned and looked up at one of the castle’s dilapidated towers and saw something small and golden shining in the afternoon sunlight. I touched Eddie’s arm and pointed.

“What’s that gold thing?”

He put a hand above his eyes and squinted. “What gold thing?”

“On the tower there. Right below the top window opening.”

Eddie looked again and then dropped his hand. “I don’t see anything.”

I beckoned Ms. Terwilliger over and tried to show her. “Do you see that? Below that window on the tallest tower?”

“It looks golden,” she said promptly.

Eddie was incredulous and turned back to where we indicated. “What are you guys talking about? There’s nothing there.” I could understand his disbelief. Dhampir vision was superior to that of a human.

Ms. Terwilliger scrutinized him for a moment before fixing her gaze back on the tower. “It’s possible we’re looking at something that can only be seen by those who perceive magic. This could be what we need.”

“Then how do we get to it?” I wondered aloud. The tower itself was little more than a high stone wall, and I wasn’t confident it offered great footholds for climbing. It was also in a section of the castle behind a fence, warning visitors to stay on the outside. With a few more tourists wandering through, plus the occasional park ranger, I knew there was no way we could covertly jump the fence.

Eddie surprised us both with a magical suggestion. “I could climb it. Can’t you guys do an invisibility spell?”

“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.

All three of us crowded around it, hoping for revelation—but got nothing. We cast more spells on it and tried pairing it with the original brick we’d brought from Pittsburgh. Still nothing. Wondering if there might be more gold bricks around, we did another search of the property but came up empty. Hot and hungry by this point, we decided to call a break and get some lunch. We went to a German restaurant and were surprised to see how crowded it and other restaurants in the park’s small town were.

“There’s a fishing convention in town,” our waiter told us. “Hope you’ve got a hotel if you were planning on staying.”

We hadn’t gotten one yet, actually, though we had been discussing staying overnight to possibly search the park again tomorrow. “Maybe we can find another nearby town,” I mused.