Ty was laid in bed and reached for his phone. It was 10:31 and he'd been laid on his mattress on his own for two hours, his heart beating so fast his chest hurt. He pulled up Livvy's text tab and started typing.

'I need you to keep a secret.'

He saw her typing bubble appear and his heart faltered.

'Is it illegal?' she replied. 'Does it involve you keeping animals in your room?'

'I kissed Kit.'

Seconds later, his bedroom door opened and Livvy ran in, shutting the door behind her and throwing herself down on the bed beside him. Her eyes were wide, but she said nothing. Instead, she crawled under the covers next to him, laying her head in the crook between his neck and his shoulder.

"Delete that conversation," Ty demanded. Livvy obliged, Ty doing the same. "Are you surprised?"

"No." Livvy shrugged, stroking his hair absently. "A little surprised, but not really."

"Livvy?"

"Yeah?"

"How…how do you date someone? How do you date a boy?" he asked quietly. Livvy turned to look at him, at his closed eyes and the lingering blush still clinging to his cheeks. She could feel his thumping hard.

"I wouldn't know," Livvy answered honestly. "I haven't ever kissed a boy. I should have been first anyway! I'm older!"

"By, like, one minute," Ty countered. He paused. "Is it..is it difficult to like someone?"

Livvy smiled. "I don't know. Do you think it's difficult?"

"I don't know. A little bit. But I like Kit," Ty answered.

"I like Kit too," Livvy said, rubbing his shoulder affectionately. "Can I stay here with you, little brother?"

Ty nodded, and put his head on her shoulder, rolling over to face her. She put a hand up and tugged on a curl that hung over his forehead.

"I love you, Ty-Ty," she whispered.

"I love you too," he answered, listening to her breath, the steady rise and fall of her chest as she fell asleep. He focused on matching his own breathing to hers until he too fell asleep.

It was Livvy who woke first, her arm flung across Ty protectively. She sat up and nudged his shoulder.

"It's pancakes for breakfast," she said happily, shaking him awake. "Come on, I wanna get in before Emma takes the last of the syrup."

Ty groaned sleepily and sat up. Livvy went over to his desk and picked up the comb he never used to run through her hair. She handed him the matching brush and he half-heartedly attempted to tame his sleep-mussed hair. She glanced at him in the mirror's reflection. He was perched on the chest of belongings behind her, angling himself to be able to see the mirror over her shoulder. She wasn't entirely sure how to begin this conversation, but who knew when she'd next get such a perfect opportunity? The two of them got a lot less time alone together nowadays.

"Ty, do you think you might be interested in a…relationship with Kit?" she asked, forcing her voice to sound casual. "Do you know what that might entail? Being in a relationship?"

"Yes," Ty answered, abandoning his hairbrush. "Dr Watson and Mary Morstan are in a relationship."

"That's true, yeah," Livvy said, nodding. "But real life relationships aren't always like the ones in the books you read. Real life relationships are more complicated than that."

"Why?" Ty asked. "Books are meant to be grounded in realism so we can identify with them. Why wouldn't they be accurate?"

"Well, because sometimes writers exaggerate things in their books to make it dramatic so it's interesting or so more people buy it," Livvy explained. "You might need to learn how to have a relationship like you had to learn to act in front of the Clave, or how to read facial expressions. But you can learn it, Ty-Ty, just like you've learnt everything else."

Ty looked at her. "Livvy," he asked seriously. "Does everyone have to learn everything like this?"

She hesitated before nodding. "Sure, just differently. We'll figure it out, the two of us. I'll help you." Ty nodded and she sat down beside him on the old wooden chest at the end of his bed, putting an arm around him. "Ty, he likes you. You don't need to change. He doesn't want whoever you think you should be to be like everyone else. He doesn't like everyone else. He likes Ty." She stood up. "Let's get pancakes. I'm starving."

When the twins reached the kitchen, everyone else was already there; Kit sat on the end of a bench engaged in some discussion about mundane horror movies with Dru. He was telling her about some movie about a woman in black that he thought she'd love when he glanced up to see Livvy and Ty. He smiled as them, blushing, and went back to his conversation with Dru.

"First pancakes are up," Julian called from the stove, and Ty grabbed a plate, going over to get it. Livvy glanced at Kit and wondered whether he felt different. Did Ty look different? She supposed not, but a first kiss was pretty…big. Was Ty even Kit's first kiss? She didn't know how to feel that it had happened to Ty before her. Maybe it was wrong of her, but she'd always assumed it would be the other way around. She swallowed down a feeling of jealousy and leaned across the table to join Kit and Dru's conversation.

"You know, Dru, we've been going to the Mundie library. I bet you could find some good horror books there."

"They'll have the book that film is based on," Kit chipped in.

Dru smiled, nodding. "I'd like that. You guys wouldn't mind if I came with you?"

Livvy shook her head. "Of course not." It occurred to her suddenly that Dru was never invted along with them. It was an age thing, but it still wasn't fair. "You're always welcome along with us," she added, and Dru cast her a grateful look.

"We could go today," Kit suggested.

"No," Ty said, sitting down beside Livvy. "We're having a meeting today about the mission yesterday. Right, Emma?"

"Absolutely right, Sherlock," Emma nodded, holding the almost-empty bottle of syrup over the heads of the Blackthorns, whose hands had shot out to grab the last drop.

Ty lifted his plate calmly out of the way of the four pairs of determined hands. Julian was attempting to calm with scuffle with an authoritative voice. It wasn't working. He sighed, casting an apologetic look at Kit.

"I bet you don't have to deal with that as an only child," he said, and Kit laughed.

"No, not really."

"No!" Dru protested as Emma poured the last of the syrup onto her pancakes. Emma laughed, dipping a finger in the small puddle of stickiness and dotting it on the end of Dru's button nose.

"Damn right," Emma grinned triumphantly.

"Emma said 'damn'," Tavvy said, scandalised. Ty reached for his headphones and put them on to drown out the chaos, spearing a bite of pancake in resignation. He and it exchanged an amused look, and Ty kicked gently at Kit's ankle as he looked away.

As soon as everyone had finished eating, Emma stood up.

"Meeting in twenty minutes. Library. We need to talk about what we found out at the beach ad whether it will actually help us identify this mystery demon."

Kit was the first to leave, even though he was ready and the twins were still in their pyjamas. Ty got up to follow him and opened his mouth to call the boy's name. He felt strangely tongue-tied though after last night, and turned off up the stairs before Kit could notice him.

Ty was in his element. The meeting was in full swing and while everyone else sat fairly absently taking it in, Ty was scribbling notes and leaping to his feet at intervals to get tall stacks of books, flipping through indexes and shoving in scraps of paper to mark relevant pages. By the time the meeting was over, everyone else was looking down at their half page of notes whilst Ty flipped through his extensive scrawlings and copied passages from books.

"Look, we might be here for a while. Does anyone want a drink?" Julian offered. There was a clamour of agreements but Ty didn't react. "Ty?" Jules asked, getting no reply. He tapped on his brother's book gently with the end of his pen. He didn't want to startle him; when Ty was focused, there was nothing outside himself and what he was focused on. Ty looked up, pushing his headphones down. "Drink?" Julian repeated.

"I'm busy," Ty replied, and went back to his books and notes. There were diagrams nobody else properly understood, and shorthand that no one but Livvy could truly decode. Kit had to smile at the state of Ty's hair, which seemed to be growing messier the more excited he got. He really was like a detective, Kit thought. He would hate to be any police officer trying to decipher his scribblings that, whilst very neat, seemed to have no explanation or link to one another.

"Photophobic. Smoke. Emitting high noise when injured," Ty whispered to himself over and over. Livvy rested her cheek on the table, watching him piece everything together. It was one of her favourite things to do. Ty was rarely happier than when he got to play detective. It was his very favourite thing, ordering everything and putting all the puzzle pieces together that no one else could begin to understand. He yanked on a curl and repeated the words, faster this time. He looked around at the arch of books spread before him and suddenly made a leap of triumph, jumping to his feet and darting off into the book stacks. Livvy and Kit exchanged a look and burst out laughing.

Livvy could hear Ty muttering to himself quietly, eventually letting out a frustrated noise of annoyance.

"We don't have it! We need this book and we don't have it!" he said in annoyance. He appeared from between the book stacks, hair in a state of disarray and hands opening and closing.

"Come and sit down. We'll find it," Livvy said soothingly.

"I can tell you what this demon is if I have this book. I need it now," he said, panic creeping into his voice. He turned as Julian walked in, carrying a tray of drinks. "Take me to the New York Institute."

"Slow down, slow down. What's happening?"

"I know what this demon is," Ty said, hands flapping at his sides. Kit was struggling to decide whether he was stressed or excited or both. He started shuffling Ty's papers together into a neat pile and paper-clipped them together. "But I need a book and we don't have it. The New York library is bigger. There's a higher chance they'll have it. We have to go now."

"You have a lead?" Julian asked, amazed. "I left for two minutes. How have you…?"

"Julian!" Ty said desperately.

"Okay, calm down. I'll call Clary and Jace."

Ty sprinted off, stopping only to grab up the notes Kit had bundled together with a grateful smile, leaving the others looking between each other wondering how one teenage boy, five books, and some notes could crack open a case that no one else could make heads nor tails of.

Ty and Julian stood before the portal, waiting for the surface to come into whirring life. Emma had managed to convince the others to stay home, arguing over the clamour of protests that it was stupid for all of them to go retrieve one book. Julian glanced across at Ty, shifting from foot to foot restlessly, and smiled, a wave of affection rocking him. Ty was still staring impatiently at the portal, waiting for the New York side to open.

"I'm really excited to find this book so we can know what demon we're up against," he said.

"I know. Thank you for helping us, Ty-Ty. It would have taken Emma and Mark and I months to do this on our own."

"I like it. It's interesting and…relaxing."

"You don't seem very relaxed," Julian commented.

"I'm having fun. Looking for this book, and solving all the clues; it's like doing a crossword. You fit all of the right answers in, and they interlock, and then the highlighted squares give you your answer," Ty said excitedly. Julian put an arm around him, hugging his brother against him. The portal made a low whirring noise like the fan of a computer and Ty looked up at James.

"Go ahead," Julian said, giving him permission to jump into the portal, which he did, Jules himself only a second behind.

When Julian came through the portal, Ty was already about to take off to the library. Clary and Jace were waiting by the portal, looking startled.

"Ty, come and say hello," Julian said firmly. "It's rude to just run off when you get here."

"Don't worry," Clary said, smiling. "He's got a job to do. We understand." She raised a voice to talk to Ty. "Hi, Ty!"

"Hello, Clary. Hello, Jace," he called back, and ran off.

Julian shook his head fondly and turned to the others. "Thanks for having us. We won't be long."

"You're always welcome," Jace told him. "I hope we've got this book you need. What do you need it for?"

"There's this…demon on our territory. We have no clue what it is and the Clave are freaking out. I don't blame them. Whatever it is, it's killing mundanes."

"By the Angel," Clary said, shaking her head. "And it isn't in the codex? Or the encyclopaedia daemonica?"

"There's no trace of it even existing," Julian explained. "Well, except for in this book we're currently tracking down."

"Let's go help him out," Jace suggested. "That library is huge. It'll be easier if we look together."

"Thanks." Julian smiled gratefully. "I'll let you guys lead the way."

However, by almost four that afternoon, there was still no sign of the book, and Clary and Jace seemed to be running out of various corners of the library from which to produce books. Ty was getting more and more impatient, and by late afternoon he had his headphones on and his bundle of pipe cleaners in one hand. Julian put a hand on his shoulder gently.

"Come on, Ty. We'd better head back, make sure Mark isn't covering the kitchen in sugar again," Julian said, ruffling his hair.

"No, Julian, we haven't found it yet," he said, sounding frantic.

"I know, but it looks like it isn't here," Julian replied. "I'll call around some other institutes when we get home. How about the London Institute? That has one of the biggest Shadowhunter libraries anywhere."

Ty, sat on the floor against a bookcase, pulled his legs up, rocking slightly on his heels. He squeezed his eyes closed and Julian bent down and held him tightly against his chest calmingly.

"Ty, it's okay," he said quietly. "It's okay."

"Julian? Is everything okay?" Clary asked. "Is Ty alright?"

Julian nodded. "We're okay. Just give us a minute. We'll be heading off in a minute."

"I'll go get you some water," Jace said, and disappeared, Clary behind him.

"Ty, why are you upset?" Julian asked. "I know you want to know, and that not knowing is difficult but…"

"Kit can't sleep," Ty said breathlessly, wriggling out of Julian's grasp. "He told me that he couldn't sleep knowing the demon was out there and he looks sick. I need this book because I need to find this demon because I want Kit to be okay."

Julian felt his heart clench and he couldn't help but feel a strong surge of pride at the amount of effort Ty was willing to go to to help a friend, at how empathetic and caring his little brother had grown up to be. Sometimes, Julian wondered if he was guilty of imagining his younger siblings as they were in the Dark War. But Ty wasn't ten anymore. He was fifteen, and it was nice to think Julian might have had a role in shaping who Ty was becoming.

"Okay," Julian said, nodding. "Okay, I understand. Let's ask Clary and Jace if they know anywhere we might be able to get this book."

"I'm sorry," Ty whispered, and Julian stroked his brother's black hair off his forehead affectionately.

"Don't be. You're a good friend for doing this, Tiberius."

They both turned at a knock on the wall near them to see Jace and Clary, her with a glass of water in hand. She handed it to Ty and he took it gratefully.

"Do you know anywhere we might be able to find this book?" Julian asked.

"Magnus might be your best bet," Jace suggested.

"Good plan. I'll call him tonight," Julian said. "Thank you."

"Thank you," Ty repeated after him. He looked at Julian. "We should get back for dinner."

"You're right. Let's go," Julian agreed.

"The portal is open. Say hi to Emma for us," Jace said.

"Tell us how the book search goes," Clary added when they were leaving.

"I will," Ty said, and gave them a smile before he and Julian stepped into the portal to take them back to L.A.

"Ty, come help the make drinks," Emma said at breakfast the next morning. "I want to talk to you."

"Where's Julian?" he asked, going over to perch on the counter where she was cutting up fruit to make smoothies.

"He has to report to the Clave about this demon in the afternoon. He's called Magnus and Alec, and they say you're welcome whenever you like."

"So I can go today?" Ty asked.

"I think Julian wants to go with you," Emma explained.

Ty considered this briefly. "How about if he portals with me this morning and then goes to the Clave meeting after. Would that work?"

Emma shrugged. "I'll ask for you when he wakes up. He ought to say yes. You're fifteen, and this is part of a mission. I can't see why that shouldn't be fine."

Julian had an extensive list of reasons why this idea was very much not fine, and yet he still ended up in the exact same situation as he had the day before, preparing to portal to NYC with Ty in tow. Magnus had texted him to say the portal was active, and Julian took a deep breath before he followed his brother through the portal's swirling, disorienting vortex. When they landed in Magnus's lounge, Julian couldn't help his inner artist mentally taking photos of the space to draw later. Whilst Julian had no clue about interior decorating, his creative eye could certainly appreciate the aesthetic of the place.

"Hey there," Magnus smiled as they staggered through the portal Magnus had opened. He turned and called over his shoulder to Alec. "The Blackthorns are here."

"All of them?!" Alec's voice replied, sounding stressed.

"Just me and Ty," Julian assured him, amused.

It wasn't long after that Alec emerged, one blue baby on his hip and a black-haired child peeking out from behind his long legs.

"You've met Rafael and Max," Alec said, hitching Max higher onto his hip. "Do you want to say hi to Julian and Ty, Rafe?"

Rafael leaned out from behind Alec's legs, waved, and retreated back shyly. Alec smiled fondly and Magnus scooped Rafael into his arms, turning to Ty.

"We have a few boxes of books in the study back there," Magnus told Ty, pointing. "I had a cursory look through last night and I couldn't see the one you wanted, but you're more than welcome to look yourself."

"Thanks," Ty said, and disappeared into the office Magnus had pointed out. Julian turned to head back through the portal, then paused. Ty was really tense about this whole demon thing, and Julian was petrified that Magnus and Alec wouldn't understand, would make it worse. What if they tried to stop him shaking out his hands like their dad used to? It would panic Ty into nausea, and Julian wouldn't be able to come back from Idris to help. His chest ached. He'd spent his entire life trying to hide Ty's differences from those who could potentially hurt him with small-minded judgement. But Alec had helped his sister accept herself, and Magnus was basically a mentor for every Shadowhunter who'd ever lived. He turned decidedly.

"Sorry, I'll get going in a second, but I just need to talk to you about Ty before I go."

"Sure, what's up?" Alec asked, bending down to pick up Max's toy octopus and hand it to him.

"It's just that Ty…Ty is autistic," Julian said, slowly. "I wanted to let you know. He might want to wear his headphones or fidget or…I know New York is pretty busy and he gets stressed in crowds. I really want to give him the freedom to do this, but I need to know you'll look after him," Julian explained anxiously. "If there are any problems, call Emma."

"Don't worry. We'll take good care of him," Magnus promised. "We understand, Jules."

"Thank you. And thanks for doing this, guys. I'd really appreciate it if you didn't mention anything about the whole Ty thing to…anyone," Julian laughed nervously. He raised his voice to call out to Ty. "Ty, I'm heading off now. Call Emma or Livvy if you need anything. I'll see you tonight."

"Bye!" Ty called back, and Jules grinned, thanking Magnus and Alec one last time before disappearing back through the portal to go to the meeting in Idris. Ty appeared from the back room not long after.

"You don't have it," he said, shrugging his backpack off. "The book, I mean."

"I didn't think so," Magnus said. "But I do know some little shops in Manhattan run by local warlocks who I think might though."

"I'll show you my notes. Would that help?" Ty asked, pulling out his papers.

"I think that would certainly help." Magnus nodded. He looked at Alec. "See? Why didn't you and your friends ever bring me this much information? Do you know how helpful that would have been?"

Alec shrugged, putting Max into a high chair at the kitchen table. They both sat down, Rafael on Magnus's lap, and Ty joined them, spreading his notes out in front of him. He had photocopied pages of the books he'd cited in his notes, the relevant parts of everything highlighted in acid green.

"By the Angel," Alec said, in shocked amusement. "You're very thorough."

"Thank you," Ty said, looking through papers. He was writing up the highlighted passages onto one page, consolidating the relevant information.

"My sister Isabelle and her boyfriend Simon are coming up to look after these two," Alec said, putting his hand out toward his youngest son, who wrapped his whole blue hand around one of his dad's long pale fingers.

"Why is he blue?" Ty asked, laying his head on the table.

"He's a warlock," Magnus told him, bouncing Rafael on his knee.

"I know, I mean why is that his warlock's mark? How is it determined?"

"Oh, um…I'm not sure," Magnus admitted. "It has something to do with the demon parent, because warlocks with the same demon parent can have the same mark."

"Does that mean Max and your friend Catarina Loss are children of the same demon, because they both have blue skin?" Ty asked curiously, not looking up from his writing.

Magnus and Alec exchanged a look. Neither of them had considered it, and Alec wasn't sure he wanted to. Magnus couldn't help but think the same. "Um, I'm not sure, Tiberius," Magnus answered.

"Tell us about the case, then," Alec said, leaning over to read Ty's notes. "This looks complicated."

"Not really," Ty shrugged. "It's easy to put it all together using the method of loci."

"What's that?" Alec asked.

"It's a way of remembering things by imagining yourself retrieving the facts from a physical space," he said, and sat back, having finished his notes.

"Where were you when the whole Shadow World was looking for the mortal mirror?" Alec laughed.

"I was nine," Ty answered. "I didn't know I wanted to be a detective then."

"We need more detective Shadowhunters," Alec mused. "It would make a lot of missions a lot easier to have someone to outsource the technical stuff to."

"I'll help if you like," Ty offered. "I was going to go to the Scholomance but they didn't accept my application."

"Well, you can always reapply; you're still young," Magnus reasoned.

"Kit yelled at them for being mean to me, so I'm not sure they'd even let me through the door," Ty explained, smiling. Magnus and Alec exchanged a look so quick Ty didn't even see it. Before they could ask anything more, a knock came on the door.

"Hello!" a girl's voice called and a girl and boy came in. Simon and Isabelle. Max gave an excited screech and Simon lifted him out of his high chair, cuddling him close.

"How are you, baby Avatar?" Simon asked, untangling Max's hair from his budding horns. "Are your daddies still not letting you watch Star Wars?"

"Don't put them through that. It's so long," Isabelle moaned.

"That's because we watched the director's cut," Simon corrected.

"Whatever," Isabelle replied, rolling her eyes. She looked to Ty and smiled as she bent down to pull Rafael into a tight hug. "Tiberius, right?"

"Oh, yeah, we met at your sister's wedding," Simon added.

Ty nodded, repacking his backpack. "I remember. You were there when I told Helen how I'd planned for the event like it was a crime scene."

"What?" Isabelle asked, looking puzzled.

"Ty wants to be a detective," Alec explained, and glanced at his watch. "Speaking of, we have some investigating to do."

After a flurry of goodbyes, and Magnus and Alec kissing their children before they went, Magnus led Ty down the stairwell and out onto the New York streets.

It was almost one fluid movement; as they stepped onto the street, Ty winced. His hands flew up to his face like he was bracing for an attack – but the only attack that was oncoming was a sensory one. As they got closer to the centre of the city, and the sun started reflecting off the windows of the skyscrapers, Ty put a hand out to block out the light.

"Come on," Alec said, veering off. "Let's take the back alleys. It's quieter there, and not as bright. The sun is really strong today," he added kindly.

"Great idea," Magnus agreed. "This first place is only a couple of blocks from here."

When they eventually came to the shop, it was small and smelled of brass and old wood. All around the walls were framed drawings of different Fey species and Ty was looking around the tapestries and art as if they were the most precious things he'd ever seen. He was pointing to all the different types, careful not to touch anything. Alec looked over at the sound of Ty whispering quietly to himself and bent down to see what he was looking it.

"Nixie, pixie, hobgoblin, mermaid, unicorn, brownie, kelpie," he was mumbling, pointing to each one in turn. He turned when he sensed Alec behind him and flushed. "Sorry."

"No, sorry, I didn't mean to sneak up on you. I was just listening to you," Alec said. "You know lots about faeries."

"I know lots about Downworlders in general," Ty told him. "You probably know lots about warlocks, because you are Magnus's boyfriend. My brother and sister Mark and Helen are half-faeries, so I wanted to know everything I could so when I'm older I can make the Clave understand too. Then they might lift my sister's exile. The Clave are too harsh to people who are different," Ty said sadly, and Magnus and Alec exchanged a look. It sounded like he was speaking from personal experience. They suspected he was. "If no one ever does anything about injustice, nothing changes. It's like what you did for Helen and Aline. They can get married because you kissed in the Accords Hall." Alec blushed. "Julian tells us that story a lot."

Magnus waved this off modestly. "You ought to intern for us with the Shadowhunter-Downworlder alliance," he added from across the room, where he was turning an ancient vase over in his hands. He put it back on the shelf and leaned against the wall. "It would be good to have a Shadowhunter who knows about Fey, especially one younger than the rest of us. You grew up in a pretty influential time in Shadowhunter history, have lived through the big political changes. No one knows the effects of those better than your generation."

"I only lived through so many changes because you and your friends initiated so many of them," Ty pointed out.

"Plus, it's useful to have someone like you who can do the same amount of research in one day it would take the rest of us together a week," Magnus finished.

Ty's grey eyes were wide and round. "Are you serious? You'd let me intern for you?"

"Sure. Ask Jules and we'll talk to him about it," Alec promised. Ty shook out his hands happily, hesitating for a moment. Sometimes, Livvy had told him, people who didn't know Ty might not understand what his hands moving meant, so it was better to find another way of expressing his happiness or anxiety. But Magnus and Alec didn't seem to mind, or even particularly notice, so Ty didn't think they would mind if he kept doing it.

"Do I hear Magnus Bane?" a voice said from nearby. The three of them turned to see a man leaning against the counter. Behind him was a curtain, separating the shop floor from what Ty imagined was the stock room. The man was tall, though he didn't look it by the way he was leant against the counter, resting on his elbows. When Magnus saw him, he went over to shake the man's hand.

"Marvin, how have you been?"

Marvin shrugged. "There's not a huge call for magical flavours when you're in town, but you settling down with a family has certainly helped business."

Magnus grinned. "Well, I'm glad to be of service."

"Last I heard, you had a husband and a couple of kids," Marvin replied, taking off the leather jacket he wore and laying it across the counter. Beneath it, he wore a light t-shirt that let Ty see the tattoos across his arms. It wasn't all that common for denizens of the Shadow World to have tattoos – he could only think of Diana's that he'd seen – and Ty went over to look at them, curious. "Is this them?" Marvin asked, glancing at Ty and Alec.

"Boyfriend, not husband," Alec corrected. "And no, this is Ty. He's from the L.A. Institute. He's on a mission; we're just his back-up. Our sons are at home."

"Ah," Marvin nodded. "I understand. You know, normally I don't let Shadowhunters in here…"

"But…?" Magnus prompted, and Marvin gave a begrudgingly small smile.

"But I like your alliance thing, and I don't think you're here to bust me."

"We aren't. We're here for a book," Ty told him, pulling his notes out. "This is it," he added, pointing to a sheet of paper with a line of writing on. It read, in neat cursive, 'Konjaku Hyakki Shūi'.

"That's a little bit niche, isn't it?" Marvin commented. "It's not exactly light reading."

"Good. I don't need it for light reading," Ty replied. "I need it to solve an important case."

Marvin huffed a laugh, looking like the act of showing amusement cost him something. As he disappeared behind the curtain to locate the book, Ty saw that Marvin – though perfectly normal-looking from the waist up – had, instead of legs, green tentacles with pink suckers. They didn't make much noise, but enough that Ty knew he would have noticed it if he hadn't been distracted earlier. He glanced briefly at the tentacles but, after deciding they weren't like any Mundie creature he'd heard of in their colouring, sat back, not particularly interested.

"You know, in history, warlocks faced worse discrimination the more obvious their marks were," Magnus told Ty, who looked horrified. "Things do change. Your sister won't always be exiled."

"Sometimes, I hate the Clave," Ty said, voice quiet but vicious. Magnus laughed as Alec shushed the boy hastily.

"Ty, Ty, be careful. We all kind of think that, but it can be dangerous to say stuff like that. The walls have ears."

"No they don't," Ty replied, puzzled. He wished Livvy was here to translate. "And besides, if everyone thinks it, who cares if someone says it?"

"He's got you there," Magnus cackled. Alec stifled a laugh.

"I think a lot of Shadowhunters think that at one point or another," Alec admitted. "The Cohort thinks the Law is too lax, and people like us think it's too strict."

Magnus mumbled something under his breath about what he thought of the Cohort, and Alec urged him to be quiet, chuckling. It wasn't long after that Marvin reappeared, book in hand. Ty beamed.

"A book like this can fetch a pretty good profit," Marvin told him. "It's quite expensive."

"Then perhaps I could just borrow it?" Ty asked earnestly. "Like a library?"

Marvin cracked a small smile that held a hint of fondness. "How about a trade? I'll give you this book in exchange for a promise."

"What kind of promise?" Ty asked. He was cautious but unsuspicious.

"When I was looking for this book," he said, laying it down on the counter. "I heard you all talking. I heard you tell those two you want to make the Clave understand Downworlders, people who are different. The Cold Peace does not bode well for the Downworld. I don't usually have a lot of faith in Shadowhunters, but I have a good feeling about you, and so I'm asking you a favour. Do you promise you'll stand up for what's right when the time comes?"

Ty nodded, and Marvin slid the book along the counter to Ty, who slipped it gratefully and carefully into his backpack.

"I'm going to be a detective," Ty told him seriously. "And that's all about finding out the truth. I don't always think the Clave are telling the truth, but then who does? Everyone is just pretending to be like everyone else. It's harder for Downworlders; you can't always hide it because you have warlock marks or vampire fangs. Some people can hide the fact they're different. But pretending to be the same as everyone else will always make you miserable. I promise, when I'm older, I'll make the Clave give up on the idea that only the people who have angel-blood and fit into their mold of perfect are people at all."

Marvin smiled a quick, genuine smile and disappeared back behind the curtain and into the back of the shop.

"Let's get you home," Alec said, as Marvin went out of view. "I'm sure your family will want to see the book."

"You'll ask Julian if I can intern for you?" Ty asked. Magnus nodded.

"Absolutely. We'll talk to him tonight."

Ty smiled, securing his backpack on his shoulders, impatient to get home and show Julian the book. They could finally tell the Clave what the demon was. And, most importantly, it might put Kit's mind at rest.