“All knowledge hurts,” he replied, and stood up, letting the book fall open in her lap. Clary stared down at the clean white page with the black rune Mark spilled across it. It looked something like a winged spiral, until she tilted her head, and then it seemed like a staff wound around with vines. The mutable corners of the pattern tickled her mind like feathers brushed against sensitive skin. She felt the shivery flicker of reaction, making her want to close her eyes, but she held them open until they stung and blurred. She was about to blink when she felt it: a click inside her head, like a key turning in a lock.

The rune on the page seemed to spring into sharp focus, and she thought, involuntarily, Remember. If the rune were a word, it would have been that one, but there was more meaning to it than any word she could imagine. It was a child’s first memory of light falling through crib bars, the recollected scent of rain and city streets, the pain of unforgotten loss, the sting of remembered humiliation, and the cruel forgetfulness of old age, when the most ancient of memories stand out with agonizingly clear precision and the nearest of incidents are lost beyond recall.

With a little sigh she turned to the next page, and the next, letting the images and sensations flow over her. Sorrow. Thought. Strength. Protection. Grace—and then cried out in reproachful surprise as Magnus snatched the book off her lap.

“That’s enough,” he said, sliding it back onto its shelf. He dusted his hands off on his colorful pants, leaving streaks of gray. “If you read all the runes at once, you’ll give yourself a headache.”

“But—”

“Most Shadowhunter children grow up learning one rune at a time over a period of years,” said Jace. “The Gray Book contains runes even I don’t know.”

“Imagine that,” said Magnus.

Jace ignored him. “Magnus showed you the rune for understanding and remembrance. It opens your mind up to reading and recognizing the rest of the Marks.”

“It also may serve as a trigger to activate dormant memories,” said Magnus. “They could return to you more quickly than they would otherwise. It’s the best I can do.”

Clary looked down at her lap. “I still don’t remember anything about the Mortal Cup.”

“Is that what this is about?” Magnus sounded actually astonished. “You’re after the Angel’s Cup? Look, I’ve been through your memories. There was nothing in them about the Mortal Instruments.”

“Mortal Instruments?” Clary echoed, bewildered. “I thought—”

“The Angel gave three items to the first Shadowhunters. A cup, a sword, and a mirror. The Silent Brothers have the Sword; the Cup and the Mirror were in Idris, at least until Valentine came along.”

“Nobody knows where the Mirror is,” said Alec. “Nobody’s known for ages.”

“It’s the Cup that concerns us,” said Jace. “Valentine’s looking for it.”

“And you want to get to it before he does?” Magnus asked, his eyebrows winging upward.

“I thought you said you didn’t know who Valentine was?” Clary pointed out.

“I lied,” Magnus admitted candidly. “I’m not one of the fey, you know. I’m not required to be truthful. And only a fool would get between Valentine and his revenge.”

“Is that what you think he’s after? Revenge?” said Jace.

“I would guess so. He suffered a grave defeat, and he hardly seemed—seems—the type of man to suffer defeat gracefully.”

Alec looked harder at Magnus. “Were you at the Uprising?”

Magnus’s eyes locked with Alec’s. “I was. I killed a number of your folk.”

“Circle members,” said Jace quickly. “Not ours—”

“If you insist on disavowing that which is ugly about what you do,” said Magnus, still looking at Alec, “you will never learn from your mistakes.”

Alec, plucking at the coverlet with one hand, flushed an unhappy red. “You don’t seem surprised to hear that Valentine’s still alive,” he said, avoiding Magnus’s gaze.

Magnus spread his hands wide. “Are you?”

Jace opened his mouth, then closed it again. He looked actually baffled. Eventually, he said, “So you won’t help us find the Mortal Cup?”

“I wouldn’t if I could,” said Magnus, “which, by the way, I can’t. I’ve no idea where it is, and I don’t care to know. Only a fool, as I said.”

Alec sat up straighter. “But without the Cup, we can’t—”

“Make more of you. I know,” said Magnus. “Perhaps not everyone regards that as quite the disaster that you do. Mind you,” he added, “if I had to choose between the Clave and Valentine, I would choose the Clave. At least they’re not actually sworn to wipe out my kind. But nothing the Clave has done has earned my unswerving loyalty either. So no, I’ll sit this one out. Now if we’re done here, I’d like to get back to my party before any of the guests eat each other.”

Jace, who was clenching and unclenching his hands, looked like he was about to say something furious, but Alec, standing up, put a hand on his shoulder. Clary couldn’t quite tell in the dimness, but it looked as if Alec was squeezing rather hard. “Is that likely?” he asked.

Magnus was looking at him with some amusement. “It’s happened before.”

Jace muttered something to Alec, who let go. Detaching himself, he came over to Clary. “Are you all right?” he asked in a low voice.

“I think so. I don’t feel any different …”

Magnus, standing by the door, snapped his fingers impatiently. “Move it along, teenagers. The only person who gets to canoodle in my bedroom is my magnificent self.”

“Canoodle?” repeated Clary, never having heard the word before.

“Magnificent?” repeated Jace, who was just being nasty. Magnus growled. The growl sounded like “Get out.”

They got, Magnus trailing behind them as he paused to lock the bedroom door. The tenor of the party seemed subtly different to Clary. Perhaps it was just her slightly altered vision: Everything seemed clearer, crystalline edges sharply defined. She watched a group of musicians take the small stage at the center of the room. They wore flowing garments in deep colors of gold, purple, and green, and their high voices were sharp and ethereal.

“I hate faerie bands,” Magnus muttered as the musicians segued into another haunting song, the melody as delicate and translucent as rock crystal. “All they ever play is mopey ballads.”

Jace, glancing around the room, laughed. “Where’s Isabelle?”

A rush of guilty concern hit Clary. She’d forgotten about Simon. She spun around, looking for the familiar skinny shoulders and shock of dark hair. “I don’t see him. Them, I mean.”

“There she is.” Alec spotted his sister and waved her over, looking relieved. “Over here. And watch out for the phouka.”

“Watch out for the phouka?” Jace repeated, glancing toward a thin brown-skinned man in a green paisley vest who eyed Isabelle thoughtfully as she walked by.

“He pinched me when I passed him earlier,” Alec said stiffly. “In a highly personal area.”

“I hate to break it to you, but if he’s interested in your highly personal areas, he probably isn’t interested in your sister’s.”

“Not necessarily,” said Magnus. “Faeries aren’t particular.”

Jace curled his lip scornfully in the warlock’s direction. “You still here?”

Before Magnus could reply, Isabelle was on top of them, looking pink-faced and blotchy and smelling strongly of alcohol. “Jace! Alec! Where have you been? I’ve been looking all over—”

“Where’s Simon?” Clary interrupted.

Isabelle wobbled. “He’s a rat,” she said darkly.

“Did he do something to you?” Alec was full of brotherly concern. “Did he touch you? If he tried anything—”

“No, Alec,” Isabelle said irritably. “Not like that. He’s a rat.”

“She’s drunk,” said Jace, beginning to turn away in disgust.

“I’m not,” Isabelle said indignantly. “Well, maybe a little, but that’s not the point. The point is, Simon drank one of those blue drinks—I told him not to, but he didn’t listen—and he turned into a rat.”

“A rat?” Clary repeated incredulously. “You don’t mean …”

“I mean a rat,” Isabelle said. “Little. Brown. Scaly tail.”

“The Clave isn’t going to like this,” said Alec dubiously. “I’m pretty sure turning mundanes into rats is against the Law.”

“Technically she didn’t turn him into a rat,” Jace pointed out. “The worst she could be accused of is negligence.”

“Who cares about the stupid Law?” Clary screamed, grabbing hold of Isabelle’s wrist. “My best friend is a rat!”

“Ouch!” Isabelle tried to pull her wrist back. “Let go of me!”

“Not until you tell me where he is.” She’d never wanted to smack anyone as much as she wanted to smack Isabelle right at that moment. “I can’t believe you just left him—he’s probably terrified—”

“If he hasn’t been stepped on,” Jace pointed out unhelpfully.

“I didn’t leave him. He ran under the bar,” Isabelle protested, pointing. “Let go! You’re denting my bracelet.”

“Bitch,” Clary said savagely, and flung a surprised-looking Isabelle’s hand back at her, hard. She didn’t stop for a reaction; she was running toward the bar. Dropping to her knees, she peered into the dark space under it. In the moldy-smelling gloom, she thought she could just detect a pair of glinting, beady eyes.

“Simon?” she said, her voice choked. “Is that you?”

Simon-the-rat crept forward slightly, his whiskers trembling. She could see the shape of his small rounded ears, flat against his head, and the sharp point of his nose. She fought down a feeling of revulsion—she’d never liked rats, with their yellowy squared-off teeth all ready to bite. She wished he’d been turned into a hamster.

“It’s me, Clary,” she said slowly. “Are you okay?”

Jace and the others arrived behind her, Isabelle looking more annoyed now than tearful. “Is he under there?” Jace asked curiously.

Clary, still on her hands and knees, nodded. “Shh. You’ll frighten him off.” She pushed her fingers gingerly under the edge of the bar, and wiggled them. “Please come out, Simon. We’ll get Magnus to reverse the spell. It’ll be okay.”

She heard a squeak, and the rat’s pink nose poked out from beneath the bar. With an exclamation of relief, Clary seized the rat in her hands. “Simon! You understood me!”

The rat, huddled in the hollow of her palms, squeaked glumly. Delighted, she hugged him to her chest. “Oh, poor baby,” she crooned, almost as if he really were a pet. “Poor Simon, it’ll be fine, I promise—”

“I wouldn’t feel too sorry for him,” Jace said. “That’s probably the closest he’s ever gotten to second base.”

“Shut up !” Clary glared at Jace furiously, but she did loosen her grip on the rat. His whiskers were trembling, whether in anger or agitation or simple terror, she couldn’t tell. “Get Magnus,” she said sharply. “We have to turn him back.”

“Let’s not be hasty.” Jace was actually grinning, the bastard. He reached toward Simon as if he meant to pet him. “He’s cute like that. Look at his little pink nose.”

Simon bared long yellow teeth at Jace and made a snapping motion. Jace pulled his outstretched hand back. “Izzy, go fetch our magnificent host.”

“Why me?” Isabelle looked petulant.

“Because it’s your fault the mundane’s a rat, idiot,” he said, and Clary was struck by how rarely any of them, other than Isabelle, ever said Simon’s actual name. “And we can’t leave him here.”

“You’d be happy to leave him if it weren’t for her,” Isabelle said, managing to inject the single syllable word with enough venom to poison an elephant. She stalked off, her skirt flouncing around her hips.

“I can’t believe she let you drink that blue drink,” Clary said to rat-Simon. “Now you see what you get for being so shallow.”

Simon squeaked irritably. Clary heard someone chuckle and glanced up to see Magnus leaning over her. Isabelle stood behind him, her expression furious. “Rattus norvegicus,” said Magnus, peering at Simon. “A common brown rat, nothing exotic.”

“I don’t care what kind of rat he is,” Clary said crossly. “I want him turned back.”

Magnus scratched his head thoughtfully, shedding glitter. “No point,” he said.

“That’s what I said.” Jace looked pleased.

“NO POINT?” Clary shouted, so loudly that Simon hid his head under her thumb. “HOW CAN YOU SAY THERE’s NO POINT?”

“Because he’ll turn back on his own in a few hours,” said Magnus. “The effect of the cocktails is temporary. No point working up a transformation spell; it’ll just traumatize him. Too much magic is hard on mundanes; their systems aren’t used to it.”

“I doubt his system is used to being a rat, either,” Clary pointed out. “You’re a warlock; can’t you just reverse the spell?”