“Why would they do that?” Alice asks, and the room turns toward her. She raises her chin, and soldiers forward with her question. My chest bursts with pride. “What are they drawn to?”

“Onceborns, obviously,” he says.

“And aether,” Greer says.

My heart races in my chest. “What source of aether is in the middle of campus?”

Felicity’s and Fitz’s faces blanch. They’re the only veteran Scions in the room, and they’ve come to the same realization at the same time.

“Care to share with the class?” Russ huffs. “Or is this a bloodline secret?”

“Actually…” Felicity flushes. “It is.”

Somehow, I already know what she’s going to say.

“Excalibur,” she says, her voice a mixture of fear and awe. “It’s the oldest aether weapon in the world. Forged by Merlin himself, it contains so much power that it never dissipates, like ours do. Not even when its bearer releases it. Each king, each Scion of Arthur, adds to its strength every time they wield it. When the last Camlann was over, and we’d won, that Scion returned it to the stone. Shadowborn usually aren’t materialized enough to get this far. Or Sel finds them first, so I didn’t think of it, but if a lesser demon doesn’t find a specific person to hunt, they’ll seek the nearest, biggest source of aether to consume. The more they consume, the longer they can stay. And the biggest source of aether would be the sword.”

“Where is it?” Russ demands.

“Ogof y ddraig,” I breathe.

She nods. “Yes. Under the Bell Tower. And there are Gates underground too. Tons of them. Merlins sealed them hundreds of years ago, but if Lord Davis wants Nick in position to take up Excalibur…”

“Then that’s where Nick and his dad are,” I say, my chest tightening at the very thought. “We’ve got to get to them and stop Davis before he opens any more.”

Pete throws a hand up in the air. “What about the Gates up here? I know they don’t spit demons out rapid-fire, but are we going to just let them stay open?”

“I’ll go,” William says from the doorway. “I can close them.”

“How?” Pete asks.

“With this.” William produces something small from his pocket and wiggles it back and forth. A vial of blood.

Sel’s blood. I’m sure of it.