It was, in every way, unremarkable. Despite its mysterious origins, King could see nothing that made this site worthwhile … or worthy of a rain guard when the rest of the far more extravagant forum was left to brave the elements. “Why is this covered?” he asked.

Pierce scratched his head. “I’ve heard that before it was covered rain would collect there—” He pointed to the small basin. “And would leak through to whatever is beyond. They feared erosion would undermine the stability of the site and possibly the surrounding sites as well, so they covered it up. Why do you ask?”

“Just seems odd. What do you think is down there?”

“Aside from a chasm created by Zeus’s lightning bolt? The entire area surrounding this hill was a swamp before Rome was built. Today it would have been a protected wetland. They drained the swamps and built the city. Best guess is it’s an underground lake. This whole area of the city is probably full of underground rivers, too. Without the swamps, the whole system might be dry now, but really, who knows.”

King sighed. None of this was helpful. He stood to get a better look at the pit and hit his head on the low-hanging ceiling. The metal sheet sounded out like a gong. “Shit,” he whispered, knowing the guards would soon be upon them.

Ignoring the panicked whispers of Pierce and the distant voices of the guards, King focused his attention on the pit. Once again, there were no markers of any kind. Then he looked up at the ceiling. Its plain surface held no clues, either, but the two I-beams supporting the ceiling did. They were separated by five feet, each crossing over the circle of stones. He mentally stripped the ceiling away and pictured the I-beams over the circular pit.

King jumped into the pit, scouring every surface for something more.

“Did you find something?” Pierce asked, joining him at the bottom of the two-foot-deep depression. “The guards will be here any second!”

“The I-beams,” King said. “From above, they cross over the circle.”

Pierce saw the image in his mind. The symbol of the Herculean Society. But not quite. The circle was broken. “Help me move this,” Pierce said, taking hold of the misaligned stone. “Pull it back into the circle!”

The guards’ voices grew louder. Commanding. They’d found the bodies and discovered they hadn’t passed out, but had been knocked out. The squeal of distant sirens—police and medical—converged on the forum, which would soon be an inescapable quagmire of men in uniform.

And the stone wasn’t budging.

“We’re trying to force it,” Pierce said. “Maybe it’s a more complicated lever.” He placed his hands on top of the stone like he was about to do CPR chest compressions. “You pull. I’ll push.”

As the legs and feet of the approaching guards came into view, King nodded.