“This is a love charm,” said the faerie woman, nodding to a vial filled with a delicately sparkling pink substance. “No use to you, fairest child of the Nephilim. Now this would blind your opponents in a battle.”

I imagine it would, said Brother Zachariah, studying the vial full of charcoal-colored sand.

Matthew was transparently pleased to hear about the potions. Zachariah was sure Henry’s boy had been regaled with tales of the elements over dinner time and time again.

“What’s this one?” Matthew asked, pointing to a purple vial.

“Oh, another one that would be of no interest to the Nephilim,” said the woman dismissively. “What need would you have of a potion that would make the one who took it tell you all the truth? You Shadowhunters have no secrets among each other, I hear. Besides which, you have that Mortal Sword to prove one of you is telling the truth. Though I call that a brutal business.”

“It is brutal,” Matthew agreed vehemently.

The faerie woman looked almost sad. “You come of a brutal people, sweet child.”

“Not me,” said Matthew. “I believe in art and beauty.”

“You might be pitiless one day, for all that.”

“No, never,” Matthew insisted. “I don’t care for Shadowhunter customs at all. I like Downworlder ways much more.”

“Ah, you flatter an old woman,” said the faerie, waving a hand, but her face wrinkled up like a pleased apple as she smiled once more. “Now come, since you are a darling boy, let me show you something very special. What would you say to a vial of distilled stars, guaranteeing the one who carried it long life?”

Enough, said the voices in Zachariah’s head.

Shadowhunters do not make bargains for their own lives, said Brother Zachariah, and towed Matthew away by his sleeve.

Matthew flailed and squawked a protest.

The woman’s potions were in all likelihood colored water and sand, said Zachariah. Do not waste your money or make any bargains with the fey. You must be careful at the Market. They sell heartbreak as well as dreams.

“Oh, very well,” said Matthew. “Look, Uncle Jem! That werewolf is running a book stall. Werewolves are surprisingly ardent readers, you know.”

He dashed over and began to ask artless questions of a lady werewolf in a prim dress, who was soon patting her hair and laughing at his nonsense. Brother Zachariah’s attention was suddenly arrested by the warlock he had been searching for.

Wait for me here, he told Matthew, and went to meet Ragnor Fell by the side of a fire built under one of the railway arches.

As the fire leaped, it birthed green sparks that matched the clever face of the warlock and lit his snowy white hair, curling around the sterner curl of his horns.

“Brother Zachariah,” he said, nodding. “A pleasure, but I wish I had better news for you. Ah well. Bad news comes like rain and good news like lightning, barely seen before a crash.”