“Nulan has never been the subtle type.” I bit my lip. “She had a reason.”

“Maybe it’s to distract us from something else,” Eleni suggested. “She freed the prisoners from Alsar, so we can assume they’ll use the gateway to mount a surprise attack on the celestials.”

“The gateway between Azur and earth closed as soon as the first sirens went off,” said a ghost who had suddenly appeared in a corner with his nose in a book. He had huge black eyes behind thick glasses and wore frilly lace and long polka-dot socks. “It’s a precaution.”

“What are you doing still here?” Eli said. “I didn’t call you back.”

“I’m Rana Kane, the 112th head librarian of the greatest library in the entire universe, and I live here,” the ghost said, not bothering to look up from his book. “For what it’s worth, the young guardian is right. Some of the prisoners from Alsar are on their way to earth, traveling the old-fashioned way. I overheard those nasty fellows talking about it before you arrived.”

“What’s the old-fashioned way?” Eleni asked.

“By vehicles of some sort.” Rana Kane shrugged. “Of course, in my heyday, we favored horse-drawn carriages.” He turned a page in his book. “In any case, you should leave that business to the adults. All children should report to the school, where you’ll find safety and shelter.”

As if on cue, a loud explosion outside rocked the library. The crystals hanging from the ceiling knocked into each other, and several head librarians’ portraits crashed to the floor. We could hear shouting, cackling, and hissing all at once, and lightning struck the ground outside of the window. The peacekeepers had their hands full.

Papa said the Lord of Shadows had never been able to attack the school. I wondered how the orishas had protected it. “Why is the school the safest place?”

“No adults can enter the school unless they are accompanied by a child who received an invitation,” Rana Kane said, finally looking up from his book. “Though all children are free to come and go, whether or not they have an invitation.”

“Wait, are you saying any kid can get to the school?” Eli asked, his eyebrows pinched into a deep frown. “Any kid?”

“Of course,” Rana Kane said dismissively. “That’s the point—Sky Father built the school to protect all children.”

The lobby in the library went so quiet that you could hear a feather drop. Eleni gasped and covered her mouth. Zeran looked miserable, and Eli had turned a ghastly color. My stomach churned as I clutched my staff tighter.

I’d never thought about why the Lord of Shadows had recruited children into his army, but I should’ve realized that he had a reason. He’d wanted to hurt the celestials, and what better way than through their children? Rule number four: never underestimate your opponent.