"Shinsui! Shinsui, come!" Shinichi shouted down the dark alleyway, hoping that at any time the okuri-inu would peel out of the shadows and attach itself to him again. Instead, he could only hear the quiet grumble and soft scratching that meant his demon was ignoring him.

And Shinsui would eat its fellow pedestrians if it got in the mood.

It was hard to see the okuri-inu against the deep shadows. It was snuffling at something, nose buried in a trash bin and whining obnoxiously. Shinichi gave up standing on the sidewalk and calling. He was going to have to drag the demon out. He took a step into the alley when Shinsui lifted his head like it'd finally heard Shinichi's irritation, and before Shinichi could stop it, the demon was running past him and down the street.

Shinichi didn't have to think before following after it. An okuri-inu untethered and wandering the streets, not too far away from downtown Tokyo, was only going to lead to homicide cases. He had trouble following, despite the fact that pedestrians would scatter from the demon's presence even if they didn't know why they were moving away.

He couldn't yell for the demon. He didn't want to take a chance that it would be distracted from its pursuit and attach itself to someone on the sidewalk. He'd tricked the demon into becoming his companion, but he wouldn't be able to do that a second time. Shinsui wasn't the craftiest demon, but it was clever enough to see through a trick it knew about.

The demon slowed outside a bookstore, settling in to wait for Shinichi to cross the road and join him at the door. The Crystal Stopper wasn't a store he could ever remember seeing before, but his memory also wasn't the best for the mundane. He'd remembered if he'd ever solved a murder there, but everywhere else was glossed over into a smudged backdrop. Shinsui scratched at the door plaintively, whining when Shinichi stood at its side and caught his breath.

"What are you doing?" Shinichi muttered, snagging the demon's ruff and shaking his lightly. The demon squirmed under his hand, fur dissolving into wisps until Shinichi lightened his hold. Shinsui reared back on its hind legs and fell heavily into the door, trying to catch its paws on the handle. Shinichi groaned and stepped into him, the demon dissolving and reappearing behind him.

He opened the door, a bell chiming overhead, and Shinsui was slipping around him into the store. Shinichi followed after it, eyebrows rising as he got his first good look into the store. There were several customers idling in the aisles, glancing up and then dismissing him as they went through the shelves.

Shinsui ran straight for the counter at the very back of the store, dissolving around the counter and out of sight. Shinichi didn't hesitate to chase after it, dodging around book displays and browsing customers, panic making his steps long and fast, because Shinsui was going to eat someone unless he stopped the stupid monster.

"Well, aren't you a cutie?"

Shinichi stopped halfway over the counter when he realized there were stairs leading down through the floor on the other side. There was a panel shoved to the side, exposing the dimly lit stairwell that ended in foreboding darkness. The voice he heard drifted up, and he couldn't see Shinsui anywhere.

"How'd you get all the way out here? I haven't seen one of you..." The voice trailed away, but there wasn't any screaming yet. He still had time.

No one paid him any mind as he climbed down the stairs, the darkness abruptly drawing away as he landed on the bottom step. He blinked to chase away the disorientation and found himself in a replica of the store above, the same patrons browsing the aisles and suddenly paying him more attention than before.

That was the moment when he noticed that they weren't the same patrons. They had the same clothes, the same accessories, the same expressions, but they weren't human. A bird-like man was browsing the best-seller titles. A woman with no face was flipping through a book of landscape photographs. The others had abnormally shaded skin, greens and blues and reds and yellows he'd never seen on anything humanoid, and horns growing out of their hair.

Shinsui was laying on its back, paws flapping in the air as a stranger scratched its belly and made cooing noises. The stranger was the most human-looking in the store, no strange skin-tone or horns, but there were three white tails and a pair of white ears attached to the stranger that suggested they were not clip-on accessories.

The stranger looked up, meeting Shinichi's eyes and widening his eyes. Shinsui rolled upright, trotting back to Shinichi and rubbing at his legs. Shinichi dropped his hand to the top of the demon's head, scratching at its ears.

"Oh. Is he yours? I haven't seen one of them bind themselves to a human before," the stranger said, springing upright and walking over. His tails swirled in the air behind him.

"It's my responsibility," Shinichi said, eyes narrowing on the tall, furry ears that arched through the stranger's hair. They were perked forward, the left ear twitching when the bell rang and one of the customers left the shop.

"You came in the other door." The stranger snapped his fingers. "That's what's different."

Shinichi glanced past the stranger, eyebrows arching up in surprise when he noticed that the door opened out onto the street, no stairs leading up, no sloped entrance, just right back out to the very street he'd left.

"What's going on?" Shinichi asked, taking a step back and trying to find the grip between too much and too little that would have Shinsui following him.

"Nothing's going on," the stranger said, lips curving down into a frown. His eyes scanned over Shinichi and Shinsui, lingering on the demon. He brightened immediately, offering his hand. "I'm Kuroba Kaito, owner of The Crystal Stopper. Welcome!"

"Kudou Shinichi," Shinichi replied, because it was only fair to introduce himself. He looked at the hand carefully before he shook it.

Nothing happened.

"Is this your first time stepping through?" Kuroba asked. He dropped down to kneel in front of Shinsui, bringing his hands up to hold the demon's face. Shinichi expected Shinsui to snap, draw back its lips and expose its fangs at the least.

Instead, the demon sighed and nearly went limp in Kuroba's hands.

"How did you do that?" Shinichi asked, because he'd tried everything, but no one would have believed him if he tried to explain he needed a way to pacify a demon dog.

"Sending off dogs are easy to please. They just want a little love and attention. It also helps to meet their eyes and be polite when greeting them." Kuroba leaned forward and pressed a kiss on the demon's muzzle, smacking his lips loudly for effect. "They turn into such sweethearts."

Shinichi had seen Shinsui bite through a man's tendons when he'd tried to evade arrest. Sweetheart wasn't the term he'd use.

"Anyway, you never answered, but I guess I can assume this is your first time stepping through." Kuroba sprung back to his feet, a bounce that sent his tails flailing wildly. Shinichi stared.

"What are you?"

Kuroba's eyebrows jumped, mouth falling open in shock and then he was stepping in close, hissing between his fixed smile. "Very, very rude question. Kudou-kun, you never, ever ask anyone outright. Depending on who you're asking, you could be forced into their service or eaten. Since this is your first time through, I'll let it go. But you've been warned."

"Kuroba-san, I'm ready to check out." The faceless woman approached them, a small stack of photography books in the cradle of her arm. Her chin tilted downwards, and Shinichi assumed she was looking at Shinsui. "Hello. Nice to meet you."

Shinsui barked.

"Right this way, Fujioka-san," Kuroba said, sweeping his arm towards the register and patting Shinichi on the shoulder. "Wait right here, Kudou-kun."

Shinichi hadn't planned on going anywhere, but Shinsui started prowling down the aisles and he felt duty-bound to monitor the demon. He scanned the store as he did, still unsure how he'd walked down and ended up at street-level. The darkness in the stairs couldn't have disguised the fact that they went straight down with no weird turns. The view through the storefront was the same view from before.

The customers seemed content to ignore Shinichi entirely, now that Shinsui was approaching them with placid steps and a sweet disposition. Several customers scratched the demon's ears, patted its back, and one customer, a male humanoid with green skin, dark hair and horns curled like a ram's, pulled out a treat for the demon.

Shinichi trailed the demon, running his fingers over the spines of books. There was a blend of new and used books, modern and classic, every genre he'd ever heard about, and a plethora of books he had never heard of. A few of the books warmed under his touch, shifted their letters about, or shuddered and rustled their pages, which only unsettled him even more until he caught sight of some more familiar titles. Shinsui waited patiently as he pulled down The Sign of Four and flipped it open.

The type-faced words blurred together and he was staring into a moving image of Sherlock Holmes, his thoughts forming and disappearing across the top of the page. The image dissolved again, becoming standard type-face words. He watched it cycle through the process, Sherlock's face exactly how he'd always pictured it to be, one not like any of the actors who's portrayed him or the figure that graced the dust jackets.

"I bet you've never seen one of these before," Kuroba said, reading over his shoulder. Shinichi twitched in surprise at the unexpected voice. "Watch the book, now."

The image of Sherlock twisted, features becoming more angular than before, even the nose sharpening and lengthening.

"It's because I'm reading the book over you shoulder. My image of Sherlock Holmes and yours blends together because we're both viewing the page. It's an illusion technique embedded in the ink. It reacts to conscious visual stimuli." Kuroba reached around him and touched one of the placards on the shelves. "This symbol here. Any of my shelves marked with that are illusion-type books."

"You sell magic books here?" Shinichi returned the book, stepping away from Kuroba as he did.

"I sell all books here. Biggest collection outside of Jinbouchou. The neighborhood, not a particular shop, by the way," Kuroba bragged, straightening up and spreading his arms. "I have anything and everything, and a few things that are neither real or material."

Shinichi looked around the store, estimating the size of the building and how it was possible for that statement to be true. Kuroba caught him staring.

"This is just the first floor, as it were, and not even the full length." Kuroba grabbed his arm and pulled Shinichi towards the back of the store. Shinsui obediently heeled him, content to follow them instead of running off on its own. Kuroba turned left before the reached the counter, walking between two aisles and straight for the middle section, one filled with shelves. Shinichi was about to dig in his heels, but Kuroba gave an impatient tug and they were bypassing the sections on either side.

"That's not magic, just a vision trick." Shinichi craned his neck around to see the space they had passed through, the towering sides and plain flooring giving the illusion of reduced depth, as if there was a solid wall lined with shelves instead of a doorway between two shelves.

"Oh, it's a magic trick. Just not traditional magic. I'm a big fan of modern, human magicians. I'd planned to be one when I was younger, but..." Kuroba trailed away, still holding Shinichi's wrist in his hand and guiding him through a maze of shelves. The lighting flickered in corners of the room, dimming and brightening in what reminded him eerily of a pulse.

"So you opened a magic book store instead." Shinichi didn't even mind the guiding hand, knowing he'd be lost in the labyrinth of aisles if left on his own.

"Inherited. My father owned the store before me." And there was something falsely prideful in Kuroba's tone, enough that Shinichi could guess it wasn't because his father wanted to enjoy retirement. Kuroba looked Shinichi's age, if not a year older. "You know, I never actually asked, but what brought you to my store, Kudou-kun?"

"Shinsui smelled something in an alleyway and followed the scent here."

"Is that so?" Kuroba released him, dropping back down to Shinsui's level and offering his hand. The demon came forward immediately, resting its chin in Kuroba's palm.

Shinichi shifted uncomfortably as Kuroba and the demon stared at each other. The lights in the room flared bright, nearly blinding compared to the dim flickering, and Kuroba's face was blank and neutral. He rose on his heels without the bouncy spring from earlier and turned calculating eyes on Shinichi. His tails stirred languidly and his ears slanted forwards, melting the easy going atmosphere into something oppressive.

"You know, I never got the story about how you and Shinsui here became bound together," Kuroba said, a small orb of light popping into existence at the tip of his middle tail.

"I couldn't leave him out in the forest, not after what he'd done for me." Because Shinsui had saved his life when it'd lunged at the suspect trying to kill him, when Shinichi was sure the demon had been drawn to him and attached to his shadow first. It had been a moment of mercy, because Shinichi had stumbled before the suspect was on him, and he'd read about how quickly okuri-inu would strike down their prey.

And he'd offered the demon a chance to take him at the end. If Shinsui would follow him for now, it could give him a final sending off. Then the demon had simply waited for Shinichi to catch his breath and gather himself together from where he was sprawled on the ground beside the bloodied legs of his suspect.

Kuroba's eyes softened and eight balls of light popped into existence around him, hovering in the air around his head like a halo. He reached up and plucked one down, white light spilling around his fingers and dripping down his palm.

Shinsui barked rapidly, two sharp sounds that sent his ears ringing. It pressed into Shinichi's legs, tongue lolling out and tail wagging. Shinichi placed a hand over the demon's head, its fur more substantial than he'd ever felt it before, like running his fingers through crisp fall leaves.

"I have a case for you, Kudou-kun," Kuroba said, and Shinichi realized he never said what he did for work. Kuroba offered his handful of light. "And a gift to help you solve it."

Shinichi hesitated before opening the palm of his free hand. Kuroba's closed fingers pushed into the skin of Shinichi's palm and then they were drawing away, leaving behind something warm and thundering and spilling over his palm until he closed his hand around it. The white light buzzed, vibrating against his fingers, and the light became fainter and fainter.

Shinichi brought his eyes up from his hand and they widened in shock. Kuroba no longer looked totally human, the faintest changes in his jaw and forehead adding canine lines to his face, the suggestion that his mouth could easily twist into a muzzle. He could still see three tails at his waist, but five more of pure white light floated in the air around them, impossibly long and detailed.

Shinsui became even fainter, a living and breathing dog-like shadow that only showed glittering eyes and gleaming white teeth serrated and fit in rows like a shark's mouth.

A single twisting beam of light curled around his own shoulders, one end wrapped around his waist and the other reaching out to pull at its brothers.

"What did you do?"

"A temporary gift," Kuroba said, fingers wiggling and teasing the light wrapped around Shinichi. "I know you're new to stepping through, but Shinsui promises you're intelligent. And I have high hopes for you, once you've gotten your feet. When you do, come back to see me and I'll give you a case no one has ever been able to solve."