“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.”

Malcolm Fade waved a hand over his own cup. Purple sparks woke and danced in his glass. The red wine stain on the carpet unfurled like a flower and turned to purple smoke. Hypatia looked at the broken flute as if it had turned into a rat.

“I was a child in Cornwall long ago, where Atropa belladonna grows wild,” said Malcolm quietly. “I am an expert in the uses of deadly nightshade, and I have seen its cousin deadly nightsea before. Miss Carstairs is right. She has saved our lives.”

“Seize the mermaid,” Hypatia said between her teeth.

Anna was already up and out of her chair, dagger in hand, her movements light as a cat’s. Arabella was fumbling in her bodice, her teeth bared, but Anna caught at her wrist, twisting it hard. An item fell from Arabella’s fingers and rolled upon the golden carpet: it was the horn of a sea creature, sharpened to a deadly point.

“Let me end my life,” Arabella hissed, writhing, but Anna continued to hold her prisoner with an arm about her neck. Runes flared along Anna’s bare, slender arm; the dagger in her other hand glimmered like diamonds. “Let me die with honor as sea people do.”

“Honor? There is no honor in poison. It is a coward’s trick,” said Hypatia. “You intended to poison me and Malcolm Fade. And to what end? What power do you seek?”

“She seeks revenge,” said Malcolm. “I have heard of you, Arabella. You considered yourself insulted by the Nephilim years ago. It must have been a much greater matter than any of us realized, for when Hypatia told you they were here tonight you sought to pay them back.” His eyes narrowed. “Hypatia and I would have been dead—warlocks poisoned by Shadowhunters, you would claim. Every Downworlder in London would have been after Nephilim blood.”

Her face like stone, Hypatia picked up a small golden bell and shook it; the ringing echoed through the room. A blue-skinned faerie girl with foxgloves in her hair popped her head in through the door. “You rang, mistress?”

Hypatia’s mouth was a tight line. “Hyacinth. Have the guards take this mermaid away and put her in the wine cellar.”

“Please reconsider putting a poisoner in the wine cellar,” said Matthew. “I beg of you, for the sake of my future visits.”

Hypatia waved a hand. “Put her in the Whispering Room, then. She shouldn’t be able to cause any trouble there; we’ll take her to the Spiral Labyrinth shortly.”

“And then?” said Cordelia as two trolls wearing coats with gold braid entered, detached Arabella from Anna’s grip, and escorted the hissing mermaid out of the room. “What happens to her?”

“A trial,” said Hypatia. “A Downworlder matter of no interest to you. It will be fair. Downworlders are always fair.”

“Then you should have little issue with offering Cordelia assistance,” said Anna, brushing dust from her cuffs. “As she saved your life.”

“Anna is right,” said Malcolm. “A debt is a debt. What is it you wish for help with, Nephilim?”

Cordelia let Matthew tell the tale; the picnic, James’s vision of the shadow realm, the demons who came in daylight, the wounded Shadowhunters, and the poison the Silent Brothers could not cure.

“Your friend saw a shadow land nobody else can see?” said Hypatia. “Is he the child of the shape-changing warlock girl, and the Shadowhunter mad enough to marry her? I knew that would be trouble.”

Matthew looked furious. Cordelia said, “He can indeed see what others cannot. It is a rare talent.”

“So this is a kind of demon that comes in daylight,” said Malcolm. “And transmits a poison your scholars have never seen before.”

“If such demons were free in London, it would not be good for anyone,” said Anna.

“Of course, all demons come from other worlds,” said Hypatia. “But if you think that as the children of demons we are intimately familiar with their geography and those who dwell in them, you are quite mistaken.”

“We are not insulting you, Miss Vex,” said Cordelia. “But you have your ear to the ground of Downworld. Nothing happens in it that you do not know. If there was other word of these strange demons…”

“There is not,” Hypatia said firmly. “All discussion has been about the lack of demons in London, in fact, and how strange it is.”

“Ragnor called it ‘the calm before the storm,’ but he is a doomsayer at the best of times,” said Malcolm.

“Well, they seem to be returning,” said Anna. “A cluster of Shax demons appeared in Seven Dials just the other day.”

“And Deumas demons were encountered in the City,” Matthew added. “Nasty, messy sorts of creatures.”

Hypatia and Malcolm exchanged a look. Demons were everyone’s problem, Downworlders and Shadowhunters alike. A single attack against Shadowhunters by unknown creatures was one thing, but Shax and Deumas demons were indiscriminate killers.

“There was a rumor,” said Malcolm, “though it was only a rumor, mind, that some sort of powerful individual—a warlock, perhaps—put out the word among the demon groups that London was to be avoided.”

“Since when have demons ever listened to anyone?” inquired Anna.

Malcolm shrugged. “As I said, a rumor. Besides, in such a situation, it seems wise to leave well enough alone.”

“The time for leaving well enough alone has passed,” said Cordelia. “These sunlight demons may be a harbinger of worse to come for us all; surely we should work together to discover if that is the case?”

“I detest it when Shadowhunters make sense.” Hypatia sighed. “Ragnor Fell is back in London, and he has often worked with Shadowhunters in the past. He knows a great deal about demon worlds, having made himself a student of dimensional magic. If there is a dimension that breeds demons who can withstand sunlight, he would know about it.”

“It does seem a place to start. How do we find him?” said Matthew.

“I will send him an urgent message,” said Hypatia. “He will contact you.” She sank back into her chair. “Now go,” she said, closing her starry eyes. “I find myself weary of angels.”

There seemed little else to say. Matthew, Anna, and Cordelia made their way back through the main room of the salon, where a vampire was reciting poetry about blood. In moments they had reached Berwick Street and the outside world: Cordelia inhaled lungfuls of cool night air. It tasted of dirt and city.

“Nephilim!” It was the blue-skinned faerie girl Hypatia had called Hyacinth. She looked around at the city in distaste before handing Matthew a velvet-wrapped bundle. “Fade wished you to have this,” she said. “He is grateful for what you all did. What did you do?” she added curiously. “I’ve never heard of a warlock being grateful before.”

Anna winked at her. “I’ll tell you the story in a moment.”

Cordelia and Matthew looked at Anna in surprise. Hyacinth blushed and giggled her way back down the alley.

“I’m going to linger a bit longer,” Anna said, with a catlike stretch. “You two can take the carriage; I’ll make my own way home.”

Matthew pulled back a corner of the velvet. Folded gently within were perhaps a half-dozen blades of fine and careful faerie workmanship.

Matthew whistled. “A real gift.” He looked at Cordelia with admiration, his bronze hair gleaming in the naphtha light. “I would never have guessed Arabella was engaged in poisoning.”

“I told you earlier,” said Anna, gesturing for the carriage. “I never do court dull girls.”

DAYS PAST: PARIS, 1902

“You must go to Paris,” Matthew had said to Thomas the day before Thomas left for Madrid. He, James, and Matthew were sprawled in their chairs in the Devil Tavern, waiting for Christopher. “If you are finally getting to flee this dull island for someplace cultured, you must go to Paris first.”