There was no time to thank her. Another demon lunged; James seized his seraph blade. “Zerachiel!” he cried, and the blade became a wand of fire.

His friends were in the thick of battle—save Grace, who had backed away, clutching the dagger. James spared a bitter thought for Tatiana, who had never been willing to let Grace train to fight, before spinning to fend off a reaching demon. Before he could, a crackling seraph blade sliced sideways into the creature’s flesh. It hopped back, hissing like a pot on the boil, leaving James with a clear line of sight to Christopher. He stood holding the seraph blade, which sputtered like a frying potato.

“Christopher,” said James, “what is that thing?”

“A seraph blade! I have tried to enhance it with electricity!”

“Does that work?”

“Not at all,” confessed Christopher, just as a demon flew shrieking at his face. He stabbed it, but his seraph blade leaped with an erratic line of fire. Lucie and Thomas were both there before the demon could touch Christopher, Lucie’s axe and Thomas’s bolas almost meeting in the creature’s flesh. It winked out of existence, but another took its place immediately, rising above them like a menacing cloud.

Abandoning the seraph blade, Christopher seized a dagger from the inside of his waistcoat and stabbed it into the creature. It staggered back, just at the moment that a long spear soared through the fog and slammed into it. It folded like a letter and vanished, leaving a smear of ichor behind.

James looked over wildly and saw Alastair Carstairs, holding a matching spear in his left hand and looking thoughtfully at the spot from which the demon had just vanished.

“You’re carrying spears?” James demanded.

“I never leave the house without my spears!” cried Alastair, causing them all to stare, even Grace.

James had questions, but no chance to ask them. He heard his sister shout, and he dashed forward only to find Lucie and Cordelia fighting back-to-back, a dagger in Lucie’s hand and Cortana in Cordelia’s. Cortana formed a wide golden sweep, and every creature who managed to sneak past Cordelia’s guard, Lucie stabbed. Matthew stood atop the railing, hurling one chalikar after another to provide cover for the girls.

A demon loomed suddenly behind Thomas, whose bolas was wrapped around another demon: possibly around its throat, though with these creatures it was hard to tell.

“Lightwood!” shouted Alastair. “Behind you!”

James knew it was Alastair, because nobody else would be such a fool as to shout that in the middle of a fight. Of course Christopher turned, and of course Thomas, who the shout was aimed at, did not. James dived for Thomas, rolling on the ground to reach him faster, just as the demon lunged. Its teeth and claws raked Thomas’s arm, drawing blood. There was no room for Thomas to use his bolas. He yelled and punched the demon: it staggered and James, rising to his feet, stabbed it through the back.

But there was no time to rest: more demons had come. Matthew leaped down from the railing and ran toward them. He threw himself to the ground and slid the last few feet across the wet pavement—a great sacrifice for Matthew, who loved his clothes—hurling a chalikar into the mass of demons. One went down, but there seemed a dozen others. Alastair was hurling spears with deadly accuracy, Cordelia was laying about her with Cortana like a warrior goddess. They were all fighting well, and yet—

The largest demon rose up in front of James. Without a second’s hesitation, he plunged his seraph blade into the creature. Ichor splashed black against his hand, spattering the ground at his feet. The demon gurgled and seemed to crumple, its froglike legs giving out under it. James raised his blade to dispatch it, just as it looked up at him with its deadly black eyes.

He saw himself reflected in those eyes as if they were mirrors. He saw his own black hair, his pale face, the gold of his pupils. He saw the same expression he had seen on the face of the Deumas in the alleyway near Fleet Street.

Recognition.

“Herondale boy,” the demon said, in a voice like the last hiss of dying fire in a grate. “I know you. I know all about you. The blood of demons burns in your veins. Why would you slay those who worship your mother’s father? Why destroy your own kind?”

James froze. He could see several of the others twist to look over at him: Matthew looked furious, the others horrified. Lucie had her hand over her mouth. Alastair, who stood the closest to him, was staring with wide dark eyes.

James exhaled a shuddering breath. “I am not your kind,” he said.

“You do not know what you are.”

Enough, James thought. This is enough. “If you worship my grandfather,” he said savagely, “then go, in his name. Not back to Chiswick House—back to the dimension you came from.”

The demon hesitated, and as it did, all the other demons went still. Every figure at the riverside was turned toward James.

“We will go, then, as you say, to show that we honor your blood,” said the demon. “But there is one condition. If you or your friends speak a word of what happened here, tonight, to any member of the Clave, we will return. And your families will pay in blood and death for your betrayal.”

“Don’t you dare—!” James began.

The demon grinned. “In the name of Hell’s most cunning prince,” it said, in a voice so low only James could hear it.

Then it vanished—they all vanished. As quickly as the world had exploded into motion and noise, it went still again. James could hear the river, the harsh breath of Alastair nearby, the pounding of his own heart.

He dropped his still-burning blade to the ground. He saw Lucie and Cordelia lower their weapons. Thomas and Matthew staggered to their feet; there was a cut along Matthew’s face, and Thomas’s shirt was torn, his arm bleeding badly.

They were all staring at James. He felt numb.

He had known his grandfather was a Greater Demon. But Princes of Hell were another matter. They were fallen angels. As powerful as Raziel, but evil and rotten to the core.

Hell’s most cunning prince. He couldn’t help but look at Lucie, but it was clear she hadn’t heard the demon’s final words: she was smiling and saying something to Cordelia.

Demons lied. Why should Lucie have to torment herself over a possible untruth? His mind raced ahead: he had to talk to Uncle Jem again, as soon as possible. Jem was the one who had been looking for their grandfather. Jem would know what to do.

It was Christopher who broke the silence. “What just happened?”

“Demons vanished,” said Matthew, dabbing blood from his face. “The leader seemed to feel it was an old friend of James’s grandfather.”

“Oh, the demony grandfather?” said Christopher.

“Yes, obviously the demony one, Christopher,” said James.

“The other one’s Welsh,” said Thomas, as if this explained things. He directed this statement in Alastair and Cordelia’s direction.

“No need to explain about Herondale,” said Alastair, with an unpleasant smile. “I imagine this happens to him fairly often.”

Cordelia stepped on his foot.

Grace had emerged from the shadows. She walked toward the rest of the group, her hands clasped in front of her, her face white and stiff. “I’m sorry, I don’t know how to fight—”

“It’s all right,” James said, “it’s all right, we’ll get you trained properly—”

“James! Grace!” It was Lucie. She gestured toward the road; a second later James heard jingling, and saw an old-fashioned pony trap emerging from the fog, drawn by two scrawny brown horses. Sitting in the trap was Tatiana Blackthorn.

She pulled up short and leaped down from the carriage. As always, she presented a bizarre appearance: she was wearing a costume with full skirts and fussy lace, a dress from another age made for a much younger and plumper girl. On her head was a hat piled high with false fruit and stuffed birds. It trembled with her rage as she raked the group with her furious gaze, which came to rest on her daughter.

“Grace,” she snapped. “Get into the trap. Now.”

Grace turned to James; her face was white. In a low voice, he said, “You do not need to do as she says. Come back to the Institute with me. I beg of you.”

Grace’s face was still tearstained, but her expression had closed like a bank vault. “James. I cannot. Walk me to the carriage, please.”

James hesitated.

“Please,” she said. “I mean what I say.”

Reluctantly, James held out his arm for Grace to take. He saw Tatiana’s lips tighten into a thin line. James waited for her to snap, but she stayed silent: she had clearly not expected so many Shadowhunters there. And so many from the families she hated—Herondales, Lightwoods, Carstairs… she would wish to be gone as soon as possible, James suspected.

She glared daggers at James as he walked to the carriage, supporting Grace on his arm. He helped her in, and she sank back against the seat, her eyes closing wearily. James wished he could say something to her about the argument they’d had earlier. He and Grace had never argued before. He wanted to beg her not to go back to Chiswick House, but he suspected it would only make things worse for her if he did.

“I will write to you tomorrow,” he began.

“No,” Grace said through white lips. “No. I require some time, James. I will write to you.”

“That’s enough,” hissed Tatiana, shooing James away from the carriage. “Leave my daughter alone, Herondale. I don’t need you luring her into trouble—”

“The only trouble we encountered was your family’s Cerberus demons,” said James in a low, furious tone. “I suggest you cease with your threats, unless you wish me to tell the Clave about them.”

He couldn’t tell anyone, of course, given the demon’s threat, but Tatiana didn’t know that. Not that it mattered. A low chuckle bubbled its way up from her throat. “My demons?” she echoed. “And where are they now, Herondale?”

“Dead,” James said shortly. “We killed them.”