Teresa felt a surge of vertigo and clung to the bed to stop herself from falling. She looked at Ian.

“Are you unwell?” he asked her.

She remembered that he’d given her an injection.

“What . . . What did you inject me with?” she asked him, her voice hoarse.

He laughed in surprise.

“Insulin, obviously. Don’t you remember?”

Teresa felt weak, but she couldn’t tell if it was from lack of sleep, insufficient food, or some kind of poison running through her veins. Perhaps it was only fear.

“You know my secret, don’t you, Doctor Ian?” she asked him, gasping for breath.

Inside the cabinet behind the doctor, Teresa’s phone rang. She didn’t move.

Ian’s expression shifted. It became remote and vaguely hostile.

“Aren’t you going to pick up, Superintendent?” he asked her.

“Why don’t you answer it, Doctor Wallner?”

He closed his pale, ice-cold eyes. He didn’t much resemble the photograph from when he’d been a young man running an orphanage. Life had altered his features, and more importantly, he had cloaked his true nature with smiles and an affectionate manner; but inside, he was the same person he had always been, and Teresa could finally see him, his true nature reflected in those eyes that lacked any trace of remorse. She thought of how much strength would be required to live your whole life wearing such a heavy mask. Or perhaps it wasn’t about strength, perhaps it was some warped sense of vocation.

Teresa thought of the moment she’d shown him her diary. He’d looked at it as if he’d genuinely never seen it before. His self-control was astonishing.

“I always thought there was a monster in this case. But it’s not Andreas Hoffman,” she said. “It’s not subject thirty-nine. The true monster is the person who stole Andreas’s life from him and killed his only companion: it’s you.”

Wallner’s lips stretched into a sickening smile.

“I am a scientist, Teresa. Scientific research requires certain sacrifices to be made.”

“You killed that child, but you wanted to get rid of them both, didn’t you? Why didn’t you go back to the shelter to make sure you’d achieved your aim?”

“Oh, but I did, Superintendent. It’s just that I only found one body. I knew what the Alpha was capable of, so I fled. He was fifteen years old and possessed the physical strength of an adult. He would have killed me.”

“So you set fire to the shelter and ran away.”