"They were human, once. Their experiments have changed them too much, by now."

"What experiments?"

"They put their bodies through the wringer until they were able to extend their lives. They count as supernatural enough for the telluric currents here to keep them out."

"We got in just fine."

"Not all creatures react the same way; be glad you didn't bring your pet kitsune."

"Do they want to get at the creatures here, or at you?"

"Oh, they want me to tell them how the book works, I expect. The doctors make those who see them forget; the book helps you remember. If you've seen them, reading it will help."

"Troublesome. Are the book's effects permanent? Do they stack with repeated readings? What happens to those who have read it if the book is destroyed?"

"I've never had much chance to test it. Most of the readers hadn't ever seen the Dread Doctors. The effects are probably permanent."

"Might I see that book a moment?" she asks Lydia.

She hands her the book, observing curiously.

She begins to read it.

The sense of building dread is probably unnatural, given that she's barely gotten through the first few pages.

"This might not be the best strategy; I wouldn't expect results until you've finished more than half the novel."

She doesn't look up at him. "It can hardly hurt, can it? If my memories have been tampered with, I would prefer to know sooner. There are two others here if you wish to continue talking."

"Of course."

He begins to negotiate with Lydia.

She reads. She's a fast reader, and it's not a very thick book.

He walks to the front of his cell, dropping a small recorder through the slot.

Lydia picks it up.

The story is quiet, tense, and the sense of dread she feels matches the increasingly insecure position of the protagonists as they try to resist the Dread Doctors. 

It's when she's reading about the heroine's harrowing attempts at escape that she remembers- 

They move from point to point suddenly, jarringly.

The air around them blurs and shifts.

They walk towards her and her captives.

"...I have seen them. The first night, here, with Stiles and the chimera that was chasing him. They can- teleport?"

"They exist out of step with our reality. Don't ask me how they pulled that one off, it's harder than the immortality." 

"Is that going to affect how hard it will be to kill them."

"I expect it will be a bit of a challenge if they're prepared for you. They do exist in our reality some of the time, which makes them as vulnerable as anything else. If you can get to them without warning them, you'll have won."