He takes another swig, raising the laudanum bottle by accident, then checks himself just in time and guzzles brandy. By the time he has put it down, she has dug the mustard jar out her pocket. A smear of Soot remains in it. It sits at the bottom like a liquid piece of night.

“What is this for, Sebastian?”

He squints, takes the jar from her, flushes with excitement.

“From your mother’s bottle, yes?” He holds it close to the fire, watches the light be swallowed by its contents.

“Best to destroy it, I suppose,” he mumbles with a strange reluctance. Then a thought occurs to him, something clever, it scrunches up his face like a prune.

“You want to see it?” he mutters. “After all, what is the harm? And I can’t be there, can I? Stuck here like bait in a mousetrap, while history is being made.”

He jumps up, opens a drawer on the desk, and sorts through its contents to retrieve a small glass vial.

“Here. Another something I did not dare to destroy! Foolish. So, let’s make amends.”

Quietly, hardly daring to breathe lest it change his mood, Livia watches him drop to his knees and roll back a corner of carpet to expose the wooden floor underneath.

“Come, look,” he calls to her. “An experiment. A demonstration!”

He waits until she has kneeled down beside him, then unscrews the mustard jar and shapes a tiny island of Soot onto the floor.

“Observe,” he whispers, handing her the vial he retrieved from the desk. “What do you see?”

The vial is smooth-bodied and cylindrical, narrowing to a thin neck at the top. It takes her a moment to understand it has no opening, no stopper. A liquid fills it, heavy as treacle, but water-clear. At the heart of this substance sits a single red drop.

“What is it?” she matches his whisper. “Dye?”

“Blood! Our very last drop. Vacuum sealed. Oh, how much did we waste until I found a way of preserving it!”

“Whose blood? Mowgli’s?”

But Sebastian only shakes his head, jumps up and runs to his bed in the other room, from which he retrieves a pipette that appears to be one of many instruments strewn amongst its blankets. Without pausing for breath, he resumes his position on the floor, takes the vial from her hands, and breaks off the whole of its neck; plunges the pipette into the gelatinous liquid within; and pulls up the scarlet drop into the pipette’s glass shaft. Then he ceases all movement and bows his head, as though in prayer. Beneath their knees the floorboards are dark with decades of old sin, long absorbed into their grain. On top, like a canker, sits the abomination her mother scraped off the skin of dying murderers, looking as though it is seeping its evil into the surrounding wood.