Ida isn’t missing.

Ida is the body walker. She’s taken Maeve.

The certainty of it floods my veins with fire. My hand latches on to Sebastian’s arm, and he yelps.

“What is it?” he whispers.

My mouth flaps open, but no words come out. I lick my dry lips and try again.

“Ida.”

Sebastian’s forehead makes a deep V. “What about her?”

“No, Ida. It’s her. She’s the body walker.”

Confusion and fear grab hold of Sebastian. “What do you mean? How do you know?”

It’s safer to talk like this, I think to Sebastian. Think about it. She’s been nearby during every encounter we’ve had with the body walker. Plus, she knows we’re talented. Do you remember the way she looked at us the first time we met her? I shudder. And she wasn’t very fond of Jemma either.

Oh no. You’re right. Poor Jemma. What if she’s done something terrible with her? Sebastian’s eyes are wide and watery. What if she wants to use us?

I squeeze his arm. I won’t let that happen. We’ll protect each other. If she still has your sister, we’ll find some way to protect her too.

But the more I think about it, the more I’m sure he’s right. While body walkers don’t have to be near their victims, I’m willing to bet Ida took Maeve and Jemma to draw us out. She probably didn’t dare take us here at the Archives, where Maeve is always watching over us. But if she got rid of Maeve… Well, that makes us easier targets.

I try to focus on our task, but all I can think about is how to save Maeve without getting captured by Ida in the process.

It feels as though hours pass before Sebastian taps me on the shoulder.

Are you really going after her?

You know I have to.

What if it’s a trap? he thinks.

I’m sure it’s a trap. But if you come with me, we’ll protect each other, just like we always have.

He sighs. I will, but only because I think I found something that could protect us.

“What?!” I say out loud accidentally, then clap my hands over my mouth. One glance around reveals no one but Rachel heard us, and she just smiles and shakes her head, then returns to her book.

Why didn’t you say so earlier? What is it?

Sebastian slides the book he’s been reading over to me and points to a paragraph in the middle of the page:

The great Zinnian king Rufaldo consulted with the high priestess of the Comet and devised a plan to thwart the walker set on taking over the kingdom. He decreed that the mountain range behind the city be mined for obsidian so that his army could be outfitted with obsidian blades, arrowheads, and jewelry to protect the royal family and courtiers. Obsidian, said to be able to shield one’s mind, was the sole thing that would prevent the body walker from taking the king’s army for himself…