“Oh,” said Cordelia, surprised. The Iron Sisters were even more secretive than the Silent Brothers. Stern and removed, they shaped adamas into runed weapons for the Nephilim from their hidden fortress. They had done so for a thousand years. Like the Silent Brothers, they did not marry, and held the responsibility of placing protective spells on Shadowhunter babies when they were born. No one not of their sisterhood was allowed in the Adamant Citadel. Only women could choose to be Iron Sisters, though it seemed as lonely to Cordelia as Silent Brotherhood. “That seems very sad.”

“Indeed,” said Malcolm. “Our kind and yours are best apart, whatever Bane might say.”

“I have not met Bane,” said Hypatia, tapping her golden fingernails together. “Before he last left London he helped the Nephilim, but do they recall his graciousness, or do they only expect help at the first sign of trouble? I let you come to my salon because you amuse me, Matthew Fairchild. Because you are a child—a silly and beautiful child, who touches the fire because it is lovely, and forgets that it will burn him. Do not presume that means you can ask for favors.”

“It might be amusing for you to find out what it is they want,” suggested Anna.

“As if you don’t already know,” said Hypatia, but the look she gave Anna was a fond one, and Anna smiled.

“What if we did something for you?” Cordelia said. Arabella was making the rounds, setting her flower-bedecked drinks in front of the warlocks. Malcolm lifted his and eyed it as if he were hoping to find solace at the bottom. Hastily, Cordelia said, “What if I saved your lives?”

This time they didn’t laugh. They simply stared. “Charming,” Hypatia said. “But we are not in any danger.”

“I disagree,” said Cordelia.

She drew Cortana. Every glittering light in the room caught fire along the blade.

Cordelia struck Hypatia’s crystal flute with a sweep of her blade. The flute exploded, sending glass and wine in all directions. Arabella gave an indignant scream and Cordelia swung the sword to point directly at her.

“It’s a pity,” Cordelia said. “I’ve never met a mermaid before. I wish you hadn’t turned out to be a poisoner.”

Matthew, who had already drained his glass, set it down on the table with a loud thump. “Poison?”

“Only for the warlocks,” said Cordelia. “It was them she was trying to kill.”

Hypatia sounded outraged. “May I ask where you came to this wild conclusion?”

“My mother knows a great deal about medicinal plants, and she shared her knowledge with me,” said Cordelia. “There is a plant cultivated by the mermaids, an underwater variety of deadly nightshade, which they will not sell even at the Shadow Markets. One taste is death. I saw her sprinkle those blossoms in your cups.”