Setrakian lowered the ax. “Stand by the door. Silently. Close it behind her once she enters.” He took the lamp back from Eph, pressing the ax into his hands in trade. “She must not escape.”

He withdrew to where his walking stick stood against the wall, on the opposite side of the door—then switched off the hot lamp, disappearing into total darkness.

Eph stood beside the open cellar door, his back to the wall, flat up against it. Nora was next to him, both of them shivering in the basement of a stranger’s house. The footsteps were closer, light and soft on the ground.

They stopped at the top of the steps. A faint shadow fell over the moonlight on the cellar floor: a head and shoulders.

The footsteps started coming down.

At the bottom, just before the door, they stopped. Eph—not three yards away, the ax hugged to his chest—was transfixed by the girl’s profile. Small and short, blond hair falling over the shoulders of a modest, shin-length nightgown. Barefoot, arms hanging straight and loose, standing with a peculiar stillness. Her chest rose and fell, but no steam came out of her mouth into the moonlight.

Later, he would learn much more. That her senses of hearing and smell had become greatly enhanced. That she could hear blood pulsing through his and Nora’s and the professor’s bodies, and could smell the carbon dioxide emitted by their breath. He would learn that sight was the least acute of her senses. She was now at the stage where she was losing her color vision, and yet her thermal imaging—the ability to “read” heat signatures as monochromatic halos—had not yet fully matured.

She took a few steps forward, moving out of the rectangle of faint moonlight and into the full darkness of the cellar. A ghost had entered the room. Eph should have shut the door, but the girl’s very presence here froze him.

She turned toward where Setrakian stood, fixing on his position. The old man switched on his lamp. The girl looked at it with no expression. Then he started toward her with it. She felt its heat, and turned toward the cellar door to escape.

Eph swung it shut. The heavy door slammed hard, reverberating throughout the entire foundation. Eph imagined that the house was going to fall in on them.

The young girl, Emma Gilbarton, saw them now. She was lit purple from the side, and Eph saw glowing traces of indigo along her lips and on her small, pretty chin. Odd, like a ravegoer wearing fluorescent paint.

He remembered: blood glows indigo under ultraviolet light.