“Gross!” Meg said with enthusiasm. “Is that for medicine or something?”

“Er, no,” Will said. “You remember how Nico and I went hunting for a gift for the trogs? Well—”

“Ick.” Rachel scooted away. “Why would they want that?”

Will glanced at me like Please don’t make me say it.

I shuddered. “The troglodytes…If the legends are true…they consider lizards a great, you know…” I mimed putting something in my mouth. “Delicacy.”

Rachel hugged her stomach. “Sorry I asked.”

“Cool,” said Meg. “So if we find the trogs, we give them the lizard and they’ll help us?”

“I doubt it will be that simple,” I said. “Meg, has anyone ever agreed to help you simply because you gave them a dead lizard?”

She pondered the question so long it made me wonder about her past gift-giving practices. “I guess not?”

Will slipped the desiccated animal back in his bag. “Well, this one is apparently rare and special. You don’t want to know how difficult it was to find. Hopefully—”

Nico snorted and began to stir. “Wh-what—?”

“It’s okay,” Will reassured him. “You’re with friends.”

“Friends?” Nico sat up, bleary-eyed.

“Friends.” Will gave us a warning look, as if suggesting we shouldn’t startle Nico with any sudden moves.

I gathered Nico was a grumpy napper like his father, Hades. Wake up Hades prematurely and you were likely to end up as a nuclear-blast shadow on his bedroom wall.

Nico rubbed his eyes and frowned at me. I tried to look harmless.

“Apollo,” he said. “Right. I remember.”

“Good,” Will said. “But you’re still groggy. Have a Kit Kat.”

“Yes, doctor,” Nico muttered.

We waited while Nico refreshed himself with chocolate and a swig of nectar.

“Better.” He rose, still looking wobbly. “Okay, everybody. I’m going to lead you into the troglodyte caverns. Keep your hands away from your weapons at all times. Let me go first and do the talking. The troglodytes can be a little…jumpy.”

“By jumpy,” Will said, “Nico means likely to murder us with no provocation.”

“That’s what I said.” Nico popped the last of his Kit Kat in his mouth. “Ready? Let’s do this.”

Want directions to the troglodyte caverns? No problem!

First you go down. Then you go down some more. Then you take the next three downward turns. You’ll see a path going slightly up. Ignore that. Keep going down until your eardrums implode. Then go down even more.

We crawled through pipes. We waded through slime pits. We navigated brick tunnels, stone tunnels, and dirt tunnels that looked like they had been excavated by the earthworm chew-and-poop method. At one point, we crawled through a copper pipe so narrow I feared we’d end up popping out of Nero’s personal toilet like a bunch of beauty queens emerging from a giant birthday cake.

I imagined myself singing “Happy Birthday, Mr. Emperor,” then quickly tamped down the thought. The sewer gas must have been making me delirious.

After what seemed like hours of sewage-themed fun, we emerged in a circular room fashioned from panels of rough-hewn rock. In the center, a massive stalagmite erupted from the floor and pierced the ceiling like the center pole of a merry-go-round. (After surviving Tarquin’s Tilden Park–carousel tomb, this was not a comparison I was pleased to make.)

“This is it,” Nico said.

He led us to the base of the stalagmite. An opening had been chipped away in the floor just big enough for someone to crawl through. Handholds had been carved into the side of the stalagmite, extending down into the darkness.

“Is this part of the Labyrinth?” I asked.

The place had a similar feel. The air coming from below was warm and somehow alive, like the breath of a sleeping leviathan. I had the sense that something was monitoring our progress—something intelligent and not necessarily friendly.

Nico shook his head. “Please don’t mention the Labyrinth. The trogs detest Daedalus’s maze. They call it shallow. From here on down is all trog-built. We’re deeper than the Labyrinth has ever gone.”

“Awesome,” Meg said.

“You can go ahead of me, then,” I said.

We followed Nico down the side of the stalagmite into a massive natural cavern. I couldn’t see the edges, or even the bottom, but from the echoes I could tell it was bigger than my old temple at Didyma. (Not to brag about temple size, but that place was HUGE.)

The handholds were shallow and slippery, illuminated only by faintly glowing patches of lichen on the rock. It took all my concentration not to fall. I suspected the trogs had designed the entrance to their realm this way on purpose, so anyone foolish enough to invade would be forced to come down in single file—and might not make it to the bottom at all. The sounds of our breathing and our clinking supplies reverberated through the cave. Any number of hostiles could have been watching us as we descended, taking aim with all sorts of delightful missile weapons.

Finally, we reached the floor. My legs ached. My fingers curled into arthritic claws.

Rachel squinted into the gloom. “What do we do now?”

“You guys stay behind me,” Nico said. “Will, can you do your thing? The barest minimum, please.”

“Wait,” I said. “What is Will’s ‘thing’?”

Will kept his focus on Nico. “Do I have to?”

“We can’t use our weapons for light,” Nico reminded him. “And we’ll need a little bit more, because the trogs don’t need any. I’d rather be able to see them.”

Will wrinkled his nose. “Fine.” He set down his pack and stripped off his linen overshirt, leaving just his tank top.

I still had no idea what he was doing, though the girls didn’t seem to mind letting him do his thing. Did Will keep a concealed flashlight in his undershirt? Was he going to provide light by rubbing lichen on himself and smiling brilliantly?

Whatever the case, I wasn’t sure I wanted to see the trogs. I vaguely recalled a British Invasion band from the 1960s called the Troggs. I couldn’t shake the feeling that this subterranean race might all have mop-top hairdos and black turtlenecks and would use the word groovy a lot. I did not need that level of horror in my life.

Will took a deep breath. When he exhaled…

I thought my eyes were playing tricks on me. We’d been in near-total darkness so long, I wasn’t sure why Will’s outline suddenly seemed clearer. I could see the texture of his jeans, the individual tufts of his hair, the blue of his eyes. His skin was glowing with a soft, warm golden light as if he’d ingested sunshine.

“Whoa,” Meg said.

Rachel’s eyebrows floated toward her hairline.

Nico smirked. “Friends, meet my glow-in-the-dark boyfriend.”

“Could you not make a big deal about it?” Will asked.

I was speechless. How could anyone not make a big deal about this? As far as demigod powers went, glowing in the dark was perhaps not as showy as skeleton-summoning or tomato-vine mastery, but it was still impressive. And, like Will’s skill at healing, it was gentle, useful, and exactly what we needed in a pinch.