“You made the hollows?” Emma said. “Why?!”

Bentham turned and gazed into the fire. “It was a terrible mistake. An accident.” We waited for him to explain. It seemed to cost him real effort to drag up the story from wherever he’d hidden it away. “It was my fault for letting things go on as long as they did,” he said heavily. “I kept telling myself that my brother wasn’t as dangerous as he seemed. It was only after he imprisoned me, and it was too late to act, that I realized how wrong I’d been.”

He stepped closer to the warmth of the fire and knelt down to stroke the bear’s wide belly, letting his fingers get lost in PT’s fur. “I knew Jack had to be stopped, and not simply for my own sake—nor because there was any danger he’d ever find the Library of Souls. No, it was clear his ambitions had grown beyond that. For months he’d been molding our recruits into the foot soldiers of a dangerous political movement. He cast himself as an underdog fighting to wrest control of our society from what he called ‘the infantilizing influence of ymbrynes.’ ”

“Ymbrynes are the reason our society still exists,” Emma said bitterly.

“Yes,” Bentham said, “but you see, my brother was terribly jealous. From the time we were boys, Jack envied our sister’s power and status. Our inborn abilities were puny compared to hers. By her third birthday the elder ymbrynes who cared for us knew Alma was a great talent. People made such a fuss over her, and it drove Jack mad. When she was a baby he would pinch her just to see her cry. When she practiced turning into a bird, he would chase her and pluck her feathers.”

I saw an angry flame curl up from one of Emma’s fingers, which she extinguished in her tea.

“That ugliness only deepened over time,” Bentham said. “Jack was able to harness and exploit the same poisonous envy latent in some of our fellow peculiars. He held meetings and made speeches, rallying malcontents to his cause. Devil’s Acre was fertile ground, since many of the peculiars here were exiles, alienated from and hostile to the ymbrynic matriarchy.”

“The Claywings,” Emma said. “Before the wights became wights, that’s what they called themselves. Miss Peregrine taught us a little about them.”

“ ‘We don’t need their wings!’ Jack used to preach. ‘We’ll grow wings of our own!’ He meant this metaphorically, of course, but they used to march around wearing fake wings as a symbol of their movement.” Bentham stood up and motioned us toward the bookshelves. “Look here. I still have a photo or two from those days. A few he wasn’t able to destroy.” He pulled down an album from a shelf and turned to a picture of a large crowd listening to a man speak. “Ah, here’s Jack giving one of his hateful speeches.”

The crowd, almost exclusively male, wore big sturdy hats and were packed thirty deep, balancing on boxes and clinging to fence tops to hear what Caul had to say.

Bentham turned the page and showed us another photo, this one of two hale young men in suits and hats, one grinning earnestly, the other expressionless. “That’s me on the left, Jack on the right,” Bentham said. “Jack smiled only when he was trying to get something out of you.”

Lastly, he turned to a photo of a boy with a pair of large owlish wings that spread from behind his shoulders. He was slouched on a pedestal and regarded the camera with quiet contempt, one eye hidden behind his cocked hat. Printed across the bottom were the words We don’t need their wings.

“One of Jack’s recruiting posters,” Bentham explained.

Bentham held the second photo closer, studying his brother’s face. “There had always been a darkness in him,” he said, “but I refused to see it. Alma’s vision was sharper—she pushed Jack away early. But Jack and I were close in age and in mentality, or so I thought. We were chums, thick as thieves. But he hid his true self from me. I didn’t see him for what he was until the day I said, ‘Jack, you have stop this,’ and he had me beaten and thrown into a lightless hole to die. By then it was too late.”

Bentham looked up, his eyes reflecting the fire’s glow. “It’s quite something to realize you mean less than nothing to your own brother.” He was quiet for a moment, tangled in an awful memory.

“But you didn’t die,” said Emma. “You turned them into hollows.”

“Yes.”

“How?”

“I tricked them.”

“Into becoming horrible monsters?” I said.

“I never meant to turn them into monsters. I meant only to get rid of them.” He returned stiffly to the couch and lowered himself onto the cushions. “I was starving, near death when it came to me: the perfect story with which to ensnare my brother. A lie as old as humanity itself. The fountain of youth. With my finger I scratched it into the dirt of my cell floor: the steps of an obscure loop manipulation technique that could reverse, and forever eliminate, the dangers of aging forward. Or so it seemed. In reality, that was just a side effect of what the steps truly described, which was an arcane and largely forgotten procedure to collapse loops, quickly and permanently, in an emergency.”

I pictured the “autodestruct” button of sci-fi cliché. A supernova in miniature; stars winking out.

“I never expected my trick to work so well,” Bentham said. “A member of the movement whose sympathy I had earned circulated my technique as his own, and Jack believed it. He led his followers to a distant loop to enact the procedure—and there, I hoped, they would slam the door behind themselves forever.”