And yet the words won’t come right away. Overwhelmed by a world without a roof, they have spoken little all morning and an odd timidity clings to them yet, as though words will put in motion something irrevocable; will put a close to one part of their lives and commit them to a new one.

It’s Charlie who accepts it first.

“Do you want to go home?” he asks Livia. “To your mother?”

The girl shakes her head. She has come this far, assuming her mother’s complicity in the attack. Now she will see it out. Charlie knows better than to argue with her.

“To London, then.”

As Charlie says it, he hears the question in his own voice. It is directed at Thomas. He is their leader. They did not vote on it, nobody picked him and yet it is true, even now — especially now — that he is wounded and weak.

“I mean, if we can’t go back to Lady Naylor’s and want to do more than just sit around, it’s the only real option. ‘The Tobacco Dock, midnight, the twelfth of January.’ That’s what the ledger said in the laboratory. ‘Collect in person’: Lady Naylor will be there. She is working on something, something important, and she paid a fortune just for this one item.”

Thomas has clearly been thinking the same thing. Nevertheless there is a hesitation to his response.

“What day is it today? We were attacked on the second, and went down the mine on the third. Six days down the mine. The morning of the ninth?”

Both Charlie and Livia confirm his calculation.

“Then we have four whole days. Time enough.” He shudders slightly, squats down on his heels, steadying himself with one hand. It comes to Charlie that Thomas is very close to fainting. That he does not have the strength even to stand.

But his voice is firm.

“What we need is to talk to someone who can shed light on everything. The laboratory, the experiments, Lady Naylor’s theory of Smoke. Fresh information; some other perspective. Without it, we will continue tapping in the dark.” He juts his chin out, his mind made up. “You two go to London. I will go and see Renfrew.”

“Renfrew! But how do you know we can trust him?”

“I don’t. But he was Baron Naylor’s student, back in the day. And he is the one who told me that I was sick with Smoke. If we are right — if that cage in the laboratory is meant for me because of what is growing in me — then, Charlie, I need to know what it is for. Otherwise, I am making choices in the dark. And I am sick of doing that.”