Sin nodded. “That’s totally reasonable. Is there any particular reason you didn’t tell me you were going to do it? Is there any reason Nick had no idea until he walked into my class? Do you ever tell anyone anything?”

There was a beat, and Sin realized that it must look like she’d run through the school purely in order to abuse Alan.

His mouth twisted, color rising high on his cheekbones, as if she’d hit a sore spot. “Not often.”

Sin bit her lip. “I didn’t come down here to yell at you.”

Alan looked slightly alarmed. “Did you come down here to throw things?”

“Everything was so crazy before. We had to bury the dead, and organize a move, and I never got a chance to talk to you.”

“Did you want to?” Alan asked, sounding incredulous.

“Yes,” Sin snapped. “I wanted to say thank you.”

Alan looked startled. “For—”

“For my brother,” Sin said.

She heard her voice come out rough again. She knew she was doing this all wrong: She didn’t know how to thank someone for something like this. Sin was a Market girl born and bred. She understood bargains, she understood trading. She had always paid off her debts and tried to be fair exacting her prices.

Now all she could do was say thank you. It felt like revealing exactly how pathetic she was, that she had nothing else to offer.

She could not put a price on Toby’s life. There was nothing she had to give that could ever come close to paying back what she owed. If Alan Ryves ever asked her for anything, she would have to give it to him.

She wished he would ask for something, instead of standing there looking politely surprised.

“Cynthia,” he said, in a gentle voice she hated. That was the way he talked to children. “I would have done it for anybody.”

“I would have thanked anybody!” Sin said, and then there was a sound against the stairwell window like a storm of hail-stones.

Sin’s head turned to a window that showed a clear blue sky. Then she looked back, meeting Alan’s serious gaze, and they both flattened themselves against the walls on either side of the stairs and waited.

The sound was less like hailstones now and more like dozens of fists slamming into the window harder and harder until Sin heard a creak like ice underfoot and then the ringing, tinkling sound of glass hitting the floor.

She slid her knife out of the sheath under her shirt and eased carefully along the wall until she could peep up the stairs.

There was a nightmare creature there, tapping its way through the shards of broken glass like a fastidious old lady. It was made of mismatched bones. It had a fox skull for an elbow, and a human skull perched on top of the whole gleaming construction.

The bones were held together by bits of ribbon. Sin could see the tiny twists of fabric jerk just before the thing moved its bone limbs. They made it look like a huge, horrible puppet.

The long bones it had in the approximate place of forearms looked like they’d been taken from horses’ legs, sharpened to a point.

They didn’t have much time. Somebody was going to come investigating the noise.

Sin waited to hear the click of bones on the stairs once, twice, three times.

Then Alan stepped out from his place against the other wall, took aim, and fired. The human skull on top of the creature exploded into dust and fragments.

Somebody was definitely going to come investigating that noise. And the thing was still advancing.

Sin darted up the stairs, pressing her side to the wall. Once she was a few steps up she launched herself off the wall and into the tower of bone.

Her knife found the ribbon tying the fox skull to the horse leg. When she slashed it, the creature’s arm fell off.

She grabbed at the thing and climbed it, using the pieces of bone as handholds, and scythed ribbons to cut it off at the point that was more or less its knees.

It was still able to lash out at her, now little more than a rattling whirl of bone, like a mobile over a cradle come to life and turned savage and hungry. Shards of bone stung her face. She thrust her knife through the tangle.

The creature collapsed into a heap of knots and bone, not an instant before Sin heard someone clattering down the stairs.

Sin leaped up and away, ducking her head to hide the cuts on her face. When she glanced up apprehensively, she was in equal parts annoyed and relieved that it was only Nick.

He stood with a short sword in hand, the broken window behind him, body braced for a fight. His eyes lit on his brother. “Don’t tell me I missed all the fun.”

“Maybe next time we’ll save you some,” Alan said, grinning.

And then they heard a door open down the hall, and Sin restored her knife to its sheath. When she looked up, Ms. Popplewell was advancing, and Alan and Nick had both hidden their own weapons. Alan was wearing a very convincing air of shock and helplessness.

Nick looked vaguely homicidal, but that was sort of his default expression.

“What on earth is going on here?” demanded Ms. Popplewell.

“That’s exactly what I would like to know,” Alan said. “Does this happen often? Somebody chucked this disgusting heap through the window—any one of us could’ve been really hurt!”

The rising note of indignation in Alan’s voice was good, Sin had to admit. Damn good.

Just in case Ms. Popplewell’s eyes strayed either to the cuts on Sin’s cheeks or Mr. Tall, Dark and Homicidal, Sin decided to attract attention by covering her face and saying in a fraught whisper, “It was just so loud—”

“There, there,” Alan murmured soothingly, patting her on the back.

“I didn’t know what was going on!” Sin exclaimed. She let her shoulders go up and down once, but decided that sobbing might be a step too far.

“Has this happened before?” asked Alan, sounding scandalized.

“No!” Ms. Popplewell exclaimed, her voice harried and not suspicious at all. “Cynthia, perhaps you should go to the nurse’s office. Don’t worry about missing French.”

“Thank you,” Sin offered piteously.

Nick spoke for the first time.

“Can I go to the nurse’s office too?”

Ms. Popplewell looked at him. It obviously took her only one look to decide. “No.”

“I’m traumatized too,” Nick claimed, his voice completely flat.

“He’s a delicate flower,” Alan said under his breath.

Sin started to wend her way obediently toward the nurse’s office just in case those two brought the whole house of cards down on their heads. She made sure to keep her shoulders a little sad and hunched, lest Ms. Popplewell look after her as she went. The key to a performance was in the details.

She did cast one fleeting glance back, caught Alan’s eye, and sent him a small smile. In a flicker almost too brief to notice, the corner of his mouth turned up in response.

That evening Sin slammed into the wagon that Merris used as her office whenever she was traveling with the Market. Merris looked up from a tablet on her desk, her eyes filled with blackness. The chair on the other side of Merris’s desk was occupied by someone who had got there before Sin.

Neither of these things did much to improve Sin’s mood.

“I was attacked today,” Sin announced without greeting either of them.

“Well,” Merris murmured. Her voice always had a different inflection now that she was carrying a demon: almost like a foreign accent, a flavor of some faraway and terrible land. “We are at war.”

“Which I’d understand, if I’d been attacked by magicians!”

Merris’s office was set up to impress, with heavier furniture than a wagon should have, a charm set up on the desk that changed colors depending on whether the people in front of her lied or told the truth, and wall hangings depicting scenes from old books. One was all black strokes on red paper, and it showed a crowd of beggars trying to fight a genie, uncurling from its prison and looking murderous. Sin did not think that would go well for them.

Sin was not in the mood to be impressed. She strode across the floor and threw a small, grubby knot of ribbon down on the desk before Merris’s clasped hands.

“I know what a magician attack looks like. And I know what the necromancers can conjure up. You sent a necromancer’s sharp-edged little plaything into my school! Someone could have been hurt.”

“I take it nobody was,” Merris said. “Well done.”

Sin took a deep breath and said what she’d been burning to say for weeks.

“These tests are crazy, they are a waste of time, and they have to stop now.”

There was a silence. Sin stood at the desk because there was no chair for her and waited for the consequences. She knew what this looked like: It looked like she was weak.

She’d thought it was a joke when Merris first suggested that Mae Crawford might inherit the Market instead of Sin. It wasn’t a good joke: It was insane, offensive and hurtful, but Sin hadn’t been able to think of it as something that could actually happen.

The Davies family had traveled in the Market for four generations. Sin was the best dancer in the Market. Mae was a tourist girl who was really good at dancing for a beginner, and that was all. She didn’t know enough, she didn’t belong, and she’d been brought to the Market, by the Ryves brothers of all people, barely five months ago.

Sin hadn’t been worried.

Now she was.

Merris had set them problems about the economy of the Market that Sin hadn’t really understood. Mae had not only understood them but had come back with suggestions for improvements. A few weeks ago Merris had asked them to choose a spot in London to move the Market to, and while Sin was still asking around, Mae had got on the Internet and then on the phone. She’d chosen the location on Horsenden Hill where they were settled now, which had enough open space to house all their wagons under concealing charms. It was surrounded on two sides by a canal, and was on the site of an ancient hill fort. It was the ideal choice.

Sin knew that understanding real estate and finances wasn’t really important, was nothing more than glorified homework. She knew that it was the heart and the soul of the Market that mattered, something Mae could never touch. She just didn’t know if Merris would see it her way.

“They have to stop now?” Merris repeated, her voice crackling in weird and terrible ways. “I was under the impression I gave the orders here.”

Merris would have died if she had not let the demon Liannan into her body on the basis that she would have control during the day and the demon would take the nights. Sin knew that.

It did not make it any easier to look into her dark-brimming eyes, to hear that voice. It did not make it easy to trust Merris, especially when she no longer seemed to trust Sin.

“I agree with Sin,” said Mae from the depths of her chair.

Merris’s attention turned to Mae, both eyebrows rising. Mae did not flinch at the cold look.

Mae looked small curled up in the chair, the back rising half a foot above her pink hair. She was wearing it in pigtails today.

It was ridiculous that a tourist girl was causing Sin so many problems. This was Sin’s place.

“It’s not good strategy to keep us at each other’s throats,” Mae went on. “You said it yourself, Merris. We’re at war. Stunts like the creatures today—”

“What?” Sin snapped, and grabbed at the desk. “You sent something after Mae? She can’t fight, she’s a tourist. She could have been killed!”

“If she is going to be the leader of the Market,” Merris said, and Sin felt a chill wash all through her body in case Merris was indicating she had made a decision, “then she has to know what it is like to face danger. She handled it all right.”

“I sprayed it with a fire extinguisher,” Mae told Sin, her mouth tilting into a rueful, dimpled smile. “When it slowed down, I hit it with the fire extinguisher. Then I hit it again. It was a triumph of mind and fire extinguisher over matter.”