“Some will die anyway?” whispered a man.

“We’re mages, not miracle workers, Cloudgold,” said Osprey tiredly. “Our strength has limits, and we don’t have much time.”

“I didn’t mean anything by it,” mumbled Dedicate Cloudgold. “I’m just a librarian.”

“We are all tired,” said Crane. “We shall be more tired still before we are done. If you will erase all of your variations, Briar?”

“Everything?” demanded the boy, startled.

“We begin on cures today,” said Crane. “For that we shall need a clean slate.”

Briar obeyed, but seeing that black rectangle bare of writing made him feel almost naked. As long as instructions were there, he knew they were doing something. He had fixed on the slate to keep from thinking.

An hour later, Crane lifted the slate down and chalked in new orders. Collecting all the materials he would need to create new additives, Briar whistled cheerfully. Once again he had things to do.

That night, Rosethorn’s condition was the same.

Light filled the greenhouse workrooms the next day to announce effective blends of cancelers tested against trays full of blue pox. Several times Tris had to beg Crane to stop dictation, as she worked the cramps out of her writing hand. Osprey had moved to Crane’s table, to help her teacher mix oils and powders for tests on the disease. Everyone in both workrooms protested a stop for lunch. They knew they were close and begrudged every minute not spent in blending and testing chemicals and herbal medicines.

At the day’s end, Crane opened a cabinet at the end of his worktable, to reveal ten black glass bottles and ten dense black slabs. Someone had cut five wells three inches deep in each slab and polished the whole to a glossy finish. The bottles were sealed with layers of cloth and wax over a glass stopper. Everything shimmered with layers of magic and symbols written in power so intense it burned into Briar’s and Tris’s vision.

The black trays went to the outer workroom, where blue pox essence was put in each well. Once they were returned to Crane, he and Osprey unsealed the bottles. Acacia carried in a series of small cups, each big enough to hold a dram. Like the bottles and the stone slabs, they were written over with strong magical symbols.

“Briar,” Crane said. “Your hands are the steadiest. If you will oblige me?”

Briar shook his head. “But I dropped a tray—”

“Once,” Crane said drily. “And as often as you have made additions to the trays, you have not broken the lids, splashed the pox, nor dripped additives on your work area.”

The boy stared at Crane, astounded. How closely had the man been watching him?

“If you please?” Crane asked, raising his eyebrows.

Briar looked at his trembling hands. This was even more important than the times he knew the Thief-Lord would starve him if he rang a single bell on the chuffle-dummy’s pockets as he lifted their contents. This was more important than the risk of the docks or the mines if a hinge squeaked as he went for a jewel box. This might be Rosethorn’s life.

“Right,” he said, clenching his shuddery fingers into fists. “What do I do?”

Crane directed him to fill the cups, one for each bottle, with a liquid every bit as magically strong as anything he’d ever seen. Next he added the contents of the cups to the black stone wells. Osprey marked each slab with a glued-on patch of brightly colored cloth. Purple was for old men, lilac for old women. Red was for men in their middle years, pink for women of that age. Olive-green was young men, yellow for young women, dark blue for boys, light blue for girls. Boy infants were black; girls were white.

“Eight years,” Crane remarked softly as Briar measured and poured. “It took six of us eight years to blend these essences, to reduce the need to experiment on human beings. Xiyun Mountstrider, from Yanjing, died of breakbone fever in the third year. We thought we would never succeed without him. Rosethorn convinced us to press on. Ulra Stormborn went blind in the fifth year. First Dedicate Elmbrook took Ibaru fever and bled to death inside her skin in the seventh year, and we continued the work.”

The thought of that kind of dedication made Briar feel small and untried. I don’t know if I could do that, he confessed to Tris through their magic.

Me neither, she admitted.

“Now the first round of cures,” said Osprey. While Briar poured the human essences, she had blended five different cures from her notes and Crane’s. “Gods willing,” she whispered, adding them to the liquids in the black stone wells. “Gods willing, these will be the ones.”

That night they found Rosethorn’s condition to be the same.

The cures were unsuccessful, as they all saw the next morning. Had they worked, Crane told his staff, the blue pox would have floated to the top of each well as a white oil. The workers scrubbed and boiled the black slabs while he and Osprey created five more cures. Briar once again measured out human essences; Osprey added the new medicines when he finished. Everyone went home, to wait.

Rosethorn was no worse, but no better. Her blue spots had begun to fade. The four young people sent Lark to bed. When she woke late that evening, they made her eat.

Briar wanted to cry when they reached the greenhouse at dawn, to find these cures hadn’t worked either. Tris did cry. When the slabs were clean, they did it all again.

Returning home before sunset for the second day in a row, they found that Frostpine sat with Rosethorn. Lark and Sandry had returned to making protective oils and working them into cloth for masks and gloves. The smith went home around midnight, as Daja sat watch over their patient.