They left on the second of December, in a thin bright cold that made the frozen road ring under the hooves.
The Herzog came to say goodbye.
He had ridden from the ducal estate that morning, alone, without retinue.
He stood in the courtyard in his black riding coat, holding his gloves, and looked at Faust with the stiff, hunted expression, like proud resolved person to do a thing one does not know how to begin.
"Doctor," he said.
"Your Grace."
"I have..." He stopped. He looked at the gloves. He tried again. "My father believed a great many foolish things, and I have been, in my time, an exceptionally foolish man. You saved my wife. You helped my son." His jaw worked. "I do not have words. I have a house, and a purse, and a name. All are yours, should you ever require them."
Faust looked at the proffered hand. It was calloused from the sabre, and it trembled slightly.
He took it.
"Keep your name, Your Grace," he said. "I find it does not suit me. But I shall hold you to the house, if the winter is cold."
The Herzog's stern face broke, for an instant, into a smile that looked startlingly like his son's. He released Faust's hand and stepped back, and Rita rolled forward in her chair to press both their hands in hers.
"Write to me," she told Isfrid. "Every week. Two pages at the least."
"Mother—"
"Two pages. I am quite serious."
He kissed her forehead.
He climbed to the coachman's bench, and the cane lay across his knees, and Faust saw him lay a hand on the dragon's head, very quickly, as if touchin a friend's shoulder in passing. The metal was warm now.
"Where?" Isfrid asked, as the gates swung open.
Faust drew a letter from his coat, the last Isbert had ever dictated, scrawled in a wavering hand on the final night.
[To Master Mikuláš Rosenthal, alchemist, at the sign of the Golden Pear, in the Lesser Town of Prague. He will know more of what you seek than any man living, and he owes me an extremely large favour.]
"East," said Faust. "Prague. I hope he knows whatever remains of Hugues de Payens in the cellars of the world."
"We're not going back to Weimar? To being Inquisitors?"
"Oh, we shall still be Inquisitors. I have grown rather fond of it." Faust settled into the seat beside him, tucked the letter away, and drew his collar up against the wind. The silver case sat warm and heavy against his ribs. One more voice had joined the choir. He could feel them all, a faint chorus at the back of his mind, humming like singers tuning up.
"Come on, godson," he said. "The road is waiting, and I believe it owes us a favour as well."
Isfrid clicked his tongue. The horses stepped forward. Behind them the Frost estate stood white and silent against the winter sky, its broken tower a black tooth on the horizon, and for the first time in his life Isfrid did not look back.