Whenever someone fell through the gap between realities, plummeting straight past isthmus and into the nameless dark, they left a trail of broken memories behind. People stuttered or stopped mid-sentence, reaching for a name that had already vanished; rewriting history in their head; wondering why they kept a framed photograph of a stranger on the wall.

The Sasha Erdos Institute of Dimensional Research called them castaways. Most of them were not lucky enough to be remembered after slipping unnoticed into annihilation, but a handful of them drew attention with their sudden, conspicuous absence. So it went with the anonymous crew member aboard the Rambler. Their name and origins had been thoroughly wiped out by the abyss, but their existence could be easily surmised.

To be caught between forgetting and remembering, carrying the whole weight of recollection on the tip of your tongue, is maddening. And despite rumors to the contrary, SEIDR preferred to keep their employees sane.

The Ceremony of Remembrance was their solution to the distress of losing both person and recollection in one fell swoop. It provided comfort (in the form of platitudes) and closure (or so they claimed), and thus allowed them to wash their hands of the whole incident.

The ceremony was held in a small chapel, hidden at the back of the Institute’s library. Isaac Skinner arrived five minutes late.

As he opened the door, the hinges made a mournful, creaking noise. He winced, ducking his head, and slid onto the nearest bench.

The room was dotted with people. Blue-white lamps glowed from niches in the walls, so luminous and airy that Isaac could almost forget they were underground. At the front of the room, a sober pastor in a black robe spoke about death in a roundabout way.

“To the castaway, we will always remember that you are forgotten,” he said. His face was excessively geometric; the deep creases around his mouth were shaped like square brackets. “And we elevate you in our minds for this sacrifice. Thus, you will never be lost to history, even as the details vanish. The core of you remains, and will always remain, so long as we strive to remember that we lost so much of you.”

It was barely a step above gibberish. Isaac tuned out his words and scanned the room for Miriam.

She wasn’t there. The disappointment landed heavily on his shoulders. He’d checked all her usual haunts, from the Wizards Guild to the cafeteria; the ceremony seemed an unlikely place for her to crop up, but he thought it was worth a shot.

As he soaked in the droning voice of the pastor and the soft light, he heard a familiar voice whisper, “Make some room.”

It took Isaac a moment to recognize Harley. The last time he’d seen her, she was dazed and exhausted and covered in mud. Now she wore a clean white shirt, her golden hair tied back, eyes clear and bright. Isaac scooted over, and she sat down on the bench beside him.

“What are you doing here?” she asked.

“Playing it safe,” he whispered. “I mean, I might have met the castaway at some point. How would I know?”

“You can’t. Not for sure.”

“Exactly. So I’m here to pay my respects, just in case.”

“Smart.” Harley kicked her feet up onto the empty bench in front of them. For a bizarre moment, she reminded Isaac of Felix. “Not that it makes much of a difference. Knowing them and not knowing them. You know? I mean, I knew them and now I don’t. Basically.”

Someone near the front turned around and shushed them. Harley rolled her eyes, but she and Isaac sat out the rest of the ceremony in quiet contemplation. There was a strangely uncomfortable absence of sadness, a funeral without mourners.

Finally, the pastor burned a little figure made of bundled twigs and scattered the ashes in a bowl of water. “Rest easily,” he said. There was a collective sigh as everyone began to unwind and stand up.

Harley cracked her knuckles. “I’m heading to the NFCC after this.” Isaac gave her a curious glance, and she clarified. “New Frog Chess Club. Have you been?”

“Not yet.”

“Do you want to?”

“I’ve been meaning to go, but things keep getting in the way.” Isaac scratched his head, remembering his promise to Basil with a twinge of guilt. “I need to find a couple books from the library, but I could stop by the club after that.”

“Oh, I’ll come with you,” she said brightly. “If that’s okay. I don’t have much else to do today.”

“Oh. Sure.” Isaac didn’t often make friends, and was slightly baffled when people stepped into the role of their own accord. Not that he was complaining.

***

The books Isaac sought were all tied in some way to Oshun’s chorus, the mysterious music of the star and spheres. He was seeking one particular song, of course: the strange piano music which he’d pursued across the swamp. He remembered it clearly, every note distinct and dripping with nostalgia, but he still had no idea what it was.

At Harley’s suggestion, they split up, looking for the titles Isaac had scrawled on a yellow sticky note: Curry’s The Wize Wizard’s Guide to Songs and Noises, Lawrence’s Patterns in Alien Music, and LeGault’s Starsong.

The labyrinthine bookshelves of the library traced the outskirts of the room, circling each other in parallel, dipping back into little eddies and reading nooks periodically. They were a pleasant place to wander and a terrible place to search.

Without even realizing it, Isaac spiraled ever-deeper into the aisles. They all looked the same, lit by flickering yellow lights and covered in deep blue carpet. It was hard to tell where one row ended and the next began. As he ventured further and further from the center of the library, the noise from the cafe died away. The books swallowed all the sound around them, filling the air with a thick hush.

Isaac was more than startled when Harley emerged from the stacks just ahead of him. They both jumped.

“I just found one of them,” she said, holding up a green volume. “How did you get all the way over here?”

“Walking, mostly,” he said.

She snorted. “Not what I meant. You’re faster than you look.”

It was an odd comment, but Isaac brushed it off, taking the heavy book from Harley’s outstretched hand. It had a soft fabric cover with the word Starsong inscribed in gold leaf. “Well, that’s one down.”

“I think this is the Oshunic studies section,” Harley said, gesturing vaguely toward the shelves she’d emerged from. “The other two are probably nearby.”

They plunged back into the stacks, Harley turning left while Isaac veered to the right. He held Starsong in one hand, leafing through it and occasionally glancing down to read a line of text or examine a scratchy illustration.

When he rounded the next corner, he came face-to-face with a massive mirror.

It sliced the corridor in two, its surface clear and flawless. It was almost invisible. Isaac probably would have walked into the glass if his own reflection wasn’t standing plainly in the center of the aisle, holding a red book and staring back at him.

Something was faintly wrong with the scene. Isaac took a step back.

His reflection bared his teeth. They were dripping black.

Isaac felt the strange sensation of tipping forward, sliding uncontrollably from a dream into a nightmare. A high-pitched whine rose in his ears. Of course, there was no mirror: just him and his doppelganger, facing each other, six feet apart.

The false Isaac considered the real one for a moment, grimacing, before he twitched his fingers around thin air and spliced out of existence.

Isaac shouted, “Wait!” His voice echoed down the empty row of bookshelves.

It had only been three seconds since he turned the corner. Three seconds and his doppelganger was already gone, unreachable, dust on the wind. There was nothing Isaac could do to stop him.

With shaking hands he pulled out his phone, called SEIDR’s head of security, and said, “I just saw Caasi in the library.”

***

Raimes Kingfisher arrived ten minutes later, wearing a habitual scowl and a dark overcoat. He was accompanied by a small fleet of guards in gray dusters.

After a quick conversation with the front desk staff, they shut the library down. As the lights dimmed, people flooded out of the room in droves. Isaac watched them with his arms crossed, leaning against the wall and feeling an unshakable weariness sinking into his bones.

When Harley finally swept past him, carried with the current of evacuating patrons, Isaac waved her aside.

“What’s going on?” she asked, her gaze flicking between Isaac and the rest of the crowd. “They said the library was closing. It doesn’t normally do that.”

“Doppelganger problems,” Isaac muttered. “I might be stuck here for a while.”

“You’re serious?”

“I’m definitely not joking.”

“Damn. That’s rough.”

Isaac couldn’t argue with that.

“Well, I’ll be at the NFCC,” Harley said, drifting back toward the door. “Feel free to stop by whenever you get out of here.”

Isaac nodded, but his mind was already elsewhere. In his brain he chased Caasi along circuitous tracks of doubt before tripping over a single solid question.

How was he supposed to catch a teleporting doppelganger?

***

When Miriam Oleander strode into the library, draped in fluttering purple robes, looking as wizened and wizardly as ever, Isaac felt a sudden stab of relief. At least they would get a chance to talk.

Raimes had taken over the computers at the front desk. He was scanning through hours of security footage and absent-mindedly eating salted pistachios out of a bag. Miriam went straight to him.

“What was Caasi doing here?”

“Checking out books. According to Skinner, anyway.”

She raised an eyebrow. “Books?”

“He was holding one when I saw him,” Isaac said, peeling himself away from the wall. “He took it with him when he disappeared.”

“Odd. What book?”

“I didn’t see the title.”

“I’m trying to figure it out,” Raimes growled. “I know where he took it from, more or less. I’ve got guards checking the catalogs against the shelves, but we haven’t found anything missing yet.”

With Raimes occupied at the computer, there was little to do but wait. Isaac shifted and fidgeted and finally asked Miriam, “Can I talk to you for a moment?”

Miriam gave him a terse nod and followed him into an alcove between two bookshelves. It smelled mildly of tobacco and ink. Light filtered between the books in rectangular slivers.

Miriam said nothing, so Isaac dug his heels into the soft carpet and asked, “Am I a wizard or not?”

“I haven’t made up my mind,” she said.

“It’s been nearly a week. Do you at least know when you’ll know?” he pressed. His urgency grew by the hour. Caasi had only made it worse, appearing and disappearing like a ghost between the library shelves. It only reminded Isaac of how trapped he was in comparison.

“As soon as I figure out whether you’re incapable of strategy and caution,” she said, “or just failing to use them well.”

“I have plenty of strategy,” Isaac protested, having already accepted caution as a lost cause. “If that’s what you’re worried about—”

“It’s just the tip of the iceberg, I’m afraid.” Her eyes were dark and owlish. “If I put you on a ship, I’m accepting responsibility for whatever you do. And it seems you’re inclined to make as many mistakes as possible.”

“But I’ve learned from all of them,” Isaac said. “If I keep fucking up at this rate I’ll be a genius by summer.”

Miriam smiled unexpectedly. “Do you know why each ship has one wizard?”

Isaac blinked. “No.”

“Ever thought about it?”

“Not really.”

“Sometimes they’ll put two scientists on a ship, or two engineers, or two scribes. Weavers always work in pairs. They know how to cooperate—with a few noteworthy exceptions.” Miriam gave Isaac a pointed look which he understood perfectly. “But wizards bicker. Two good wizards with two good ideas can argue all day about which one is better.”

“I’m not bickering,” Isaac protested.

“Neither am I.”

They stood there for a few moments, in quarrelsome silence, before Isaac asked, “What if I could prove that I’m getting better? At strategy or caution or whatever you think I don’t have?”

“How would you intend to prove it?”

His earlier conversation with Harley bubbled up to the forefront of his mind. With a stroke of divine inspiration, he said, “I could beat you at chess.”

“Is that a challenge?”

“Does that mean you accept?”

Miriam gave a raspy laugh. “Absolutely. You’d need a heap of good strategy to win that match. But I have the right to kick you off my ship, end your apprenticeship, and bar you from the Wizards Guild if you lose.”

“Deal,” Isaac said firmly. He reconsidered, as he always did, just a few seconds too late.

“Good. Glad we sorted that out.” Miriam ducked out of the alcove.

Isaac followed her with the slow pace of a man hamstrung by regret. He knew immediately that he had no chance of winning. The last time he’d played chess against Miriam, he’d been demolished.

“Skinner!” Raimes called from the library front desk. “Get over here. Oleander, you too. We’ve got leads.”

“Leads, plural?” Isaac asked, hope kindling in his chest. If he managed to catch Caasi and take the cloak of reality, he’d be free to jump between Oshun and Earth without Miriam or SEIDR or anyone else getting in the way.

“It wasn’t just one book,” Raimes said grimly. “He’s been here four times in the past few days.”

“How is that possible?” Miriam asked, leaning over Raimes’s shoulder to squint at the monitor. “Don’t you people have cameras everywhere?”

“He just looks like Skinner,” Raimes said, hooking a thumb toward Isaac. “As long as he doesn’t talk, he can probably pass for human. No reason for anyone to pay much attention to him.”

“Most humans can’t teleport,” Isaac said.

“That’s the clever part. Look at this.”

Raimes pulled up a grainy camera feed pointing down onto a pair of bathroom doors. One of them swung open, and Isaac—or someone who looked just like Isaac—walked out. “He’s been using the library bathroom to get in and out. Probably appearing and disappearing inside a stall.”

“Very odd,” Miriam said. “Doppelgangers ain’t known for their subtlety.”

“What about the books?” Isaac asked. “How many has he stolen?”

“Seven. At least.” Raimes tapped a piece of paper on the desk. “That’s a list of the titles. Before you go looking for patterns, I can tell you they all have one thing in common.”

“What?”

“Mu.”

Isaac frowned. “What the hell is Mu?”

“An old Oshunic city. Prehistoric. SEIDR’s been excavating it for a while, but there haven’t been any new developments in years.”

“Is there any reason Caasi would be interested in it?”

“Not that I’m aware of.” Raimes shrugged. “But I’m no expert.”

“It doesn’t make sense,” Miriam said. “None of it.”

“Why not?” Isaac asked, scanning the book titles. They were all unfamiliar. “Maybe he’s just doing some research.”

“Doppelgangers ain’t known for their research skills, either. This is too organized.”

“Too organized?” Isaac’s voice carried a trace of irritation. “Obviously he’s been coming to the library on purpose. I don’t think it’s a coincidence that all the books cover the same subject. If he’s not researching this city, what the hell is he doing?”

“My guess is he’s working for someone else,” Miriam said.

There was a pause as Isaac and Raimes digested this.

“That seems like a stretch,” Isaac said. “If Caasi stole the samovars on his own—”

“Ah, but he didn’t. Not if he’s got an associate with an interest in Oshunic history.” Miriam began to pace in front of the desk. “When he first showed up, I assumed he just took a personal liking to the samovars, thinking they were pretty or interesting enough to steal. But that doesn’t explain him sneaking into the library, picking books off the shelves one by one, keeping his head down. Pretending to be you. There’s been some coordination here, behind the scenes, from someone more careful than any doppelganger. Caasi might be collecting the books, but I’d wager he’s not the one reading them.”

“Then who is?” Isaac felt another stab of vertigo, as if the floor was collapsing beneath his feet. In his mind Caasi stood frozen in the library corridor. A vast shadow loomed behind him.

“If I knew that, I would’ve told you already,” Miriam grumbled. “All I know is that he ain’t working alone.”

Isaac rubbed his nose. “You realize this makes everything even more complicated, right?”

“If you wanted things to stay simple you should have steered clear of SEIDR.”

Isaac scowled, but he had no defense.

“I’m going to station a few more guards in the library,” Raimes announced, breaking Miriam and Isaac’s staring contest. “I’ll keep you both updated if Caasi pops up again. In the meantime, we should probably figure out what’s so damn interesting about Mu.”

“Is that all we have to go off?” Miriam asked.

“For now.”

“Then I’ll start looking into it,” Isaac said slowly. His head was still swimming with the thought of who might be standing behind his doppelganger, pulling the strings. “And see if I can figure out what Caasi wants.”

On his way out the door, Miriam caught his sleeve and said, “How about Sunday?”

“What?”

She gave him a lopsided grin. “For the chess match. I’d like to give you some time to prepare. A week seems fair enough.”

For a moment, Isaac considered refusing—explaining that the challenge had been a terrible, spur-of-the-moment idea—asking if they could work something else out.

“Sunday sounds good,” he said. There was nothing else.

***

The New Frog Chess Club, as it turned out, was hidden inside a giant floating frog. Carved from planks of driftwood, floating in a lonely corner of SEIDR’s shipyard, its odd shape lent it a lumpy, homely charm. Isaac had seen it several times before, but only from a distance. It was much larger up close.

The bridge led straight into its open mouth, where the club’s main floor held dozens of tables painted with chessboards. The majority of them were occupied by players, focusing on the medley of pieces and occasionally reaching out to slide one across the table.

Harley was leaning over a board near the back of the room. She saw Isaac hovering near the entrance and sprang to her feet. “I didn’t think you would actually show up!” she said. “Did you solve your doppelganger problems?”

“Not even remotely,” Isaac said. “But I managed to pick up another problem along the way.”

“Oh?”

“If I don’t beat Miriam in a chess match on Sunday,” Isaac said, “she’s going to kick me out of the Wizards Guild.”

The words sounded dreamlike as they spilled out of his mouth. He couldn’t believe he was actually pinning his future on this.

“You’re kidding.”

“I wish.”

“Well,” Harley said, spreading her arms, “you sure came to the right place.”

The New Frog Chess Club was a little patch of friendly warmth in the cold caverns of SEIDR. Amber lamps hung from the ceiling, and patchwork rugs dotted the floor. Friendly chatter and cries of victory or defeat floated through the air.

After asking a few questions about Isaac’s skill level (nonexistent), Harley led him to a little nook near the back of the club. It was tucked underneath a staircase, where several chairs surrounded another chessboard. The pieces were oversized, fanciful frogs, painted in blues and greens.

“Usually we let beginners get started over here,” Harley said, “so they don’t have any spectators to worry about. It stresses some people out, you know. Being watched.”

“How do they usually get started?”

“Temur offers free lessons for two weeks if you’re new. But I haven’t seen him today.” Harley glanced around. “If you come back tomorrow, he should be able to help you. Especially once he hears about the game with Miriam. He loves a good competition.”

“Is there anyone else I can practice with? Just to get the hang of how the pieces move?” Isaac coughed. “I don’t exactly have a lot of time.”

“Good point. Let me check the lounge.”

Harley thundered up the stairs, her footsteps drumming over Isaac’s head. She returned, moments later, with a green-haired woman in tow.

“Isaac, this is Jesse Chey,” she said, beaming. “Jesse, Isaac.”

Jesse Chey sank into the chair across from Isaac. She held out a hand, black and green bracelets clacking together on her arm.“Hi.”

Isaac shook her hand. “Have we met before? You seem familiar.”

“I think we were in the same tour group,” Jesse said. “You’re the guy who fell into the lagoon, right?”

Isaac grimaced. “I sure am.”

“You already know each other? Perfect.” Harley clapped her hands together. “You can get some practice with a quick game or two, if that’s alright. I’m going to go finish my match with Colin. Let me know if you have any trouble.”

“Good luck,” Jesse said as Harley strolled off.

Isaac studied his pieces. “White moves first, right?”

“Oh. Right.” She pushed one of her pawns forward. “So, uh. What did you think of the tour?”

“It was quite the introduction.” Isaac put his own pawn forward to threaten hers. “What with the alarm going off and the ship being stolen and everything.”

Jesse took his pawn. Isaac stared at the board, scratching his head, and then he realized he could capture back with his queen.

“Yeah. I was curious about that.” Jesse’s voice was light and friendly, and yet there was an odd undercurrent of tension that Isaac couldn’t trace. “You remember the weaver, right? The one who took the ship.”

“Laurel Gray?”

“Yes. Her.” Jesse managed to take Isaac’s queen, and they wound up with a puzzling mess of pawns locking up the center of the board. “Like, I was kind of shocked after it happened. But everybody clammed up as soon as I mentioned her, like I wasn’t supposed to bring it up. They all acted like she didn’t exist.”

“I know what you mean,” Isaac said. “Like you weren’t supposed to ask that kind of question.”

“Exactly! But it seemed like everybody knew. They just didn’t want to talk about it.”

“Knew what, exactly?”

Jesse’s eyes flickered away. “Why she took the ship, I guess. And why SEIDR kept lying about it.”

“What were they lying about?” His voice was cautious. There was some kind of friction between Jesse’s words and her expression. Something she didn’t want to say out loud.

“Didn’t you hear the announcement? They said she was dead. We were the last people to see her, and she looked fine to me. How would SEIDR know what happened after that?”

“They wouldn’t,” Isaac muttered, though his thoughts were derailing as his army fell to pieces.

He enjoyed the game, and the weight of the carved frogs in his hand. He liked the solid thunk as he set them down. He did not like the confusing series of moves Jesse pulled off near the end, which led to his king being trapped behind his own pawns. She cornered him with a rook.

“Good game,” he said, pushing the king over. “Have you played a lot of chess?”

“No.” She leaned forward, her voice pitching down. “Look, can I trust you?”

“That depends,” Isaac said. “Can I trust you?”

He wanted to. Most of SEIDR’s employees were oddly distant. Even the ones he liked—Miriam and Raimes and Harley—remained vaguely inaccessible, hiding behind a wall of half-acknowledged secrets.

Jesse seemed painfully earnest in comparison. “You’re probably right to be paranoid,” she said. “But I’m just here because I got an engineering degree and didn’t know what to do with it. I didn’t know it was going to be this—this—” She waved her arms wildly, as if she could capture all of SEIDR’s lunacy with a hand gesture. “… weird.”

Isaac wondered when he’d gotten paranoid. “Neither did I. Look, do you know something about Gray? Is that why you brought her up?”

Jesse bit her lower lip, and Isaac saw the twin flames of hesitation and excitement burning in her eyes. “Alright. Did you know she was a diver?”

Isaac blinked.

He’d seen the word divers printed in Gray’s file, but it had entirely slipped his mind until now. From the look in Jesse’s eyes, it was far more relevant than he’d realized.

Before he could respond, Harley swaggered up to their table. “How’s it going over here?”

“I’m guessing you won,” Jesse said, and Isaac wondered if she was really as transparent as she seemed. She’d lost all traces of urgency in a heartbeat.

“I did, I did.” Harley glanced at her watch. “But the club is closing in ten minutes or so. Do you guys want to stop by the north cafeteria?”

“Sure,” Jesse said. “I’ll be right back. I left my bag upstairs.”

As she clattered up the stairs, Isaac was faced with the crushing disappointment of missing out on a mystery. He didn’t know when he might get another chance to talk with Jesse privately.

Perhaps more importantly, he didn’t know if he could justify pouring his time into the questionable fate of Laurel Gray while Caasi was running amok in the Institute library.

“I have to do some research on Mu,” he sighed. “But I’ll be back tomorrow. Thanks for helping me out.”

“Of course. Thanks for coming.” Harley stuck out her hand, and Isaac shook it. Her smile broadened as she pressed a small, folded piece of paper into his palm. “Member meetings are on Saturdays.”

The action was so casually clandestine that Isaac didn’t check the paper until he was back in his room with the door locked. To his surprise, it was merely a green business card which read BECOME A MEMBER TODAY! and NFCC across the bottom.

He flipped it over. Across the back, in nearly illegible handwriting, someone had scribbled break the first rule.