The Zanna Function

by Daniel Wheatley

  Escape had been in her hands, and she had botched it. Zanna slumped heavily over her desk, letting out a deep sigh that made her papers flutter and skitter away. If only she had figured this out faster, she could have been on her way to freedom right now. She could have dismantled the furnace, undone the primelock, and disappeared into the woods. Instead, she had wasted her opportunity. And there wouldn’t be another one.

  Unless . . .

  Her unfocused eyes snapped back to the papers her breathy sigh had sent scattering across the desk. She pursed her lips and blew again. The furnace wasn’t the only way to get air into the house. A breath, a single breath, could be carried in from outside. If her guess was correct about the furnace serving as a gateway, then the first few breaths the Variable exhaled when she came back into the house wouldn’t be primelocked.

  Zanna scrambled for a new piece of paper. An exhale was not that different from an inhale. Most of the gases were the same. Nitrogen, oxygen, carbon dioxide, and trace amounts of argon and water vapor. She listed all the elements and their atomic compositions, as she had in her early Chemistry classes. Nitrogen was atomic number 7, oxygen 8, argon 18. Both nitrogen and oxygen paired off in diatomic molecules. Argon was a noble gas and didn’t pair off at all.

  Then the rush stopped, and Zanna came up short, staring down at the page. The words slipped out of her mouth. “What are you doing?”

  It was an absurd idea. She couldn’t even manipulate the cube of graphite in the Laboratory that had been precisely engineered to be the most basic object in the universe. Her plan was ten times more complicated. Gases moved and bounced and were invisible to the naked eye. They would be subject to the pressure of the room and the air currents. Their coordinates would be all but impossible to pin down. And she would have to be close to the Variable. Very close.

  “That’s what you get for not figuring it out sooner,” she muttered. She had forgone the sock puppets a while ago and was just talking to herself now. “Always making things more difficult than they should be.”

  Her door opened, and Zanna jumped, fearing the Variable knew exactly what she was up to and had come to nip it in the bud. But it was just the serving tray with lunch. Zanna narrowed her eyes.

  “Trying to scare me again?” she said. “Nice try, tray. But that doesn’t count.”

  The tray didn’t make any indication whether it cared if that counted or not. It just bobbed beside her, offering its bowl of minestrone with sourdough bread and a mug of hot cider. Zanna watched the curls of steam rise from the bowl of soup and tried to anticipate how they would twist. After all, steam was a gas and would move very similarly to an exhale from the Variable. She got up from her desk and began to circle the room, the tray dutifully tagging along behind her, still offering up her lunch. The steam made a ribbon in the air that Zanna watched as long as she could before it dissipated, paying close attention to how it was torn apart by the currents in the tower room. She moved to the left, and the tray followed. She moved to the right, and the tray changed direction at once, not spilling a drop of soup. With a devious grin, Zanna scampered over her bed and into her makeshift bathroom, the research breaking into a game as she ducked under the tray and ran back to her bed, climbing her wardrobe up into the rafters of the room.

  The tray barely paused. It ascended smoothly up next to her, and she had to admit defeat, leaning back against one of the roof beams with a grin. “I suppose I’ve tormented you enough for one day,” Zanna said, wrapping her hands around the bowl of minestrone. But as she spooned up her lunch, an idea came to her, and she put the soup back. “Sorry,” she said, swinging down from the rafters. “I lied. Come on!”

  The tray followed her like a puppy as she led it over to the privacy curtain—one of those old multi-paneled ones made out of lacquered wood that aristocratic ladies were always ducking behind to throw undergarments around dramatically in black-and-white period movies. Zanna grabbed the end panel and rearranged the privacy curtain so it made a six-sided enclosure around the tray. Then she stepped back and watched.

  It took a few seconds, but her hypothesis was confirmed. The tray floated up over the privacy curtain. She patted the tray and put it back in the enclosure, rearranging the privacy curtain into a crude maze. Again, it took the direct path, up and over. Zanna frowned and reset the test, this time throwing her blanket over the top so it couldn’t just fly out. For a moment she thought she had it stumped, but then the tray appeared at the exit of her maze and bobbled over to her, seeming slightly annoyed that she still had yet to eat her lunch.

  “Okay, that’s enough,” Zanna said, taking her soup back. “And I mean it this time.” The tray bowed, apparently thankful to be free of her demands, and headed back down to the kitchen. She plopped down on her bed and pulled her legs up to her chest, gnawing at the sourdough as her mind worked.

  Pathfinding. The tray must be using a pathfinding function. It asked the house where Zanna’s Self function was and then made its way toward her. The function seemed fairly robust too. The tray wasn’t afraid to backtrack a little, if that’s what it took to get to its destination.

  Zanna put her spoon down and drew a theoretical line with her finger, sketching the different mazes she had built and how the tray had solved each one. How big an area did it search? She had been clear across the house before, and it had still never failed to find her—that had been obvious from her encounter in the basement.

  Did it ever search outside?

  Zanna stopped mid-chew. Wasn’t the mansion just a maze on a larger scale? All she had to do was get somewhere so distant that the tray had to go outside to reach her. Somewhere where the shortest route to her would make the serving tray unlock the front door.

  The chimney.

  It came to her so suddenly that she jumped and spilled the minestrone all over her sheets. But she didn’t have time to pay attention to the mess. Her mind raced. If she closed the fireplace grate behind her and climbed all the way to the top of the chimney, what would the tray do? It might bump against the fireplace grate. It might spin uselessly in the upper corner of a second-floor room. But it might—just might—think she was on the roof and wander outside to reach her. It just might be her ticket out of here.

  The rest of the afternoon stretched on and on. Zanna called the tray back up to her on the pretense of wanting a glass of water; then she made it go through a whole obstacle course made out of bedsheets and privacy curtains. Everything seemed to point to her theory being sound—the tray always found a way out of the maze, no matter how complicated she made it. But every time she felt giddiness at the thought of freedom, she had to remind herself that these were just small-scale tests. The real thing was an entirely different animal.

  Far below her, the front door opened.

  Panic gripped her tight and fast. She had spent her entire afternoon tormenting the serving tray and had completely forgotten about studying airflow. Quickly, with the desperation of a student cramming at the last minute, Zanna refreshed her memory. She decided to focus on nitrogen, as that was the most abundant element in air. The molecule was diatomic—two nitrogen atoms in a triple bond. Its gravitational function would be slight, its mass minuscule. Coordinates were the tricky part. Gas molecules weren’t arranged in nice structural lattices like graphite. Instead, they bounced off one another, the coordinates changing by the millisecond as they collided and scattered. But there was a method to it—as long as she could do the calculations fast enough. Terror thumped in her heart, but she didn’t have the time to study any further. If she put this off for one more day, she would go insane.

  She slammed a fist on her door. “Hey!” she shouted as loudly as she could. “Hey! Let me out!”

  Agonizing silence followed, and Zanna’s palms began to sweat. Every moment was another exhale gone, another handful of nitrogen lost somewhere in the house. She raised a fist to pound on the door again, but then it snapped open
, and the Variable was on the other side, smirking.

  “Well, good evening to you, too,” she said.

  Zanna did her best to scowl back and hide the trembling that had started in her fingertips. She tried to sift through the air between them, pushing through the primelocked molecules, but the effort of concentration made her eyelids drop, and she stopped. If she closed her eyes, the Variable would know she was up to something, and the plan would be ruined. Zanna had to distract her.

  “Let me out,” she said. As distractions went, it wasn’t her best effort, but the Variable’s mouth quirked slightly, amused.

  “Had enough of being cooped up in your room?” She let out a breath, and there it was. Air, free air from the outside. Carbon dioxide and nitrogen and water vapor and oxygen, just as Zanna had remembered from school. She snatched at the nitrogen, but the coordinates were wrong, her calculations of its bouncing molecules too slow. It danced out of her grasp, and her face twisted into an even harder scowl.

  The Variable still wore that bemused expression on her face, and Zanna remembered that she was supposed to say something in return. But with all her brainpower going toward manipulating the nitrogen, Zanna had completely forgotten the question she had been asked a second ago.

  “Let me out.”

  The Variable frowned. “Not if you’re going to be like that. I’ve told you before, there’s no reason why we can’t get along. It will make things so much—” She stopped in mid-sentence, eyes suddenly alert.

  Zanna stopped trying to grab the nitrogen at once, but the woman had already caught the scent of trouble. It was going to be the basement all over again—another avenue of escape wasted for nothing—unless Zanna distracted her, and quickly.

  She blurted out the first thing that came to mind.

  “I know who you are.”

  As distractions went, it was perfect. The Variable still held Zanna with that intense stare, but its focus had shifted, and the feeling was like a weight off Zanna’s chest.

  “Do you now?”

  “I do,” Zanna said, and the conviction in her voice almost surprised her. “There’s only one person you could be.”

  “And who is that?”

  The Variable exhaled again, and there was very little free nitrogen left. Zanna would not get another chance after this. So she squared her shoulders and planted her feet and swung for the fences, no matter how it tore up inside her.

  “Me.”

  And there was her chance. When the woman blinked, unable to control the ripple that went through her, Zanna made a bold attempt for the nitrogen. Everything else cleared out from her mind, as if she had swiped her arm over a cluttered table. She forgot she was locked in a tower room in a stolen Victorian mansion somewhere in the far north. She forgot about the madwoman who had imprisoned her here. She forgot about St. Pommeroy’s. She forgot about her friends and Pops. There was only nitrogen. Zanna held every shred of knowledge she had, all the calculations to pin down the coordinates of the molecules as they ricocheted off each other, and made them into one complete function.

  Everything snapped together like that first day in Dr. Fitzie’s classroom when Zanna had learned how to draw theoretical lines, only this was exponentially better. One moment, she had been juggling chemical, gravity, and coordinate functions, and the next, all that was gone, replaced by one grand function of nitrogen. She could dive into it and see the parts that made it tick, but she could also pull back and observe it from a distance. This was nitrogen, this was everything that made it exist, and it was in her head.

  Zanna swallowed to hide the grin threatening to spread over her entire face. But she needn’t have worried. The Variable had not noticed.

  “I am you,” the woman said, drawing it out so Zanna could hear the absurdity in the statement. “And how exactly does that work?”

  Zanna shrugged. The rush of holding nitrogen—even if it was just half a breath’s worth—surged through her, and she wanted to dance around with it, make it stretch and compact and bounce off the walls like a child playing with a ribbon. The sooner she could bring the conversation to a close, the sooner she could be alone again. “No, you’re right, it doesn’t,” she said. “Are you going to let me out?”

  The Variable sighed and shook her head. “Not until you’ve calmed down and proven to me that you’re not going to tear up my floors again,” she said. “I put a lot of effort into this house, you know.”

  Responses danced through Zanna’s head—quips about the real reason to keep her out of the basement and how she didn’t need to tear up the floors to escape—but Zanna held her tongue. She just shifted her weight from foot to foot and her scowl from side to side.

  “I see,” the woman said after Zanna had been quiet for half a minute. She backed out of the room. “Tell me when you’re ready to be mature about this.”

  The door snapped shut behind her. Zanna slowly counted to fifty and then beckoned to her nitrogen. It trickled down through the air and came to rest on her palm. She felt nothing change, but she knew it was there, like an invisible extension of her hand. Her mind churned with the effort of keeping its function together, since it began to slip free at the slightest distraction. But it was hers and free of the primelock, and a maniacal, triumphant laugh burst up out of her belly.

  “Laughing alone in a tower room, Zanna?” she said when the impulse had passed. “You’re right on your way to becoming a mad Scientist.”

  She pulled her nitrogen out into a long string and went into her bathroom, feeding it into the half-filled bottle of shampoo and then turning the bottle upside down so the gas bubbled to the top.

  “Be good,” she whispered, like a mother tucking her child into bed. “I have big plans for you.”

  Chapter Fifteen

  It was deep in the heart of night when Zanna threw back the covers of her bed and put her feet to the floor. She had been going back and forth on whether it was better to escape tonight or tomorrow during the day while the Variable was out. Doing it now meant Zanna would have to be absolutely silent. But doing it tomorrow risked the Variable coming home early. As the episode with the basement had proven, the house was watching her. If it could send some kind of alert, the woman would be home before Zanna was down from her tower, and everything would be ruined. It had to be in the night. This night.

  She glanced out the window as she layered on clothes and wrapped her blanket around her. It didn’t seem nearly enough to brave the bitter cold outside, but Zanna had nothing warmer. She spread one of her two bedsheets on the floor, filling it with an extra pair of shoes, a stack of blank paper and pens, and a book of puzzles she hadn’t gotten around to cracking open. On impulse, she added the crumpled report on Cedwick she had thrown in the corner. Everything else, she would have to pick up along the way. Knotting the makeshift rucksack together and slinging it over her shoulder made her feel a bit like a homeless Santa, and when she caught sight of herself in the mirror, wrapped up in her blanket and a lumpy sack on her back, she had to stifle a giggle. It felt good to laugh, because the rest of her was scared to death.

  She pulled the bell cord to summon the serving tray, holding her second bedsheet and the shampoo bottle with the nitrogen inside. When the door slid open, Zanna slipped out onto the landing. She didn’t have to look over the edge to know how treacherous the drop was down to the first floor of the mansion. Her stomach already knew.

  “Bring me five roast-beef sandwiches with Swiss cheese, five apples, and a mug of hot cider,” she whispered to the serving tray. “And a dinner roll with butter on the side.”

  The tray disappeared into the shadows below her. Zanna flipped open the cap of her shampoo bottle and let the nitrogen bubble up, catching it as it escaped. The clock had started, and there was no time to dawdle. She had to be down the tower and back up the chimney by the time the serving tray returned with her meal. She tied the four corners of her secon
d bedsheet under her shoulders to make a parachute and then filled it with her small ball of nitrogen, ignoring the part of her brain pointing out just how fragile a contraption she was trusting with her life.

  When it was complete, she stood at the edge of the landing, her mind reeling at the black stairless tower below. “But seriously,” she muttered to herself, gathering her courage even as her knees threatened to give out from underneath her. “Seriously,” she said again, her hands clenched around the bedsheet and her mind clenched around the nitrogen. “Stairs.”

  Then she jumped.

  It went to pieces immediately. A retching, sickening thud walloped her in the stomach, and she lost control of her nitrogen. She snatched at it, but its function had changed. Zanna was falling, and her mind blacked out in absolute terror.

  Gravity is just a function.

  Owin’s voice cut through her panic. Of course! She had forgotten to account for the downward acceleration of her body on the nitrogen in the parachute. That was why it had twisted out of her grip as soon as she’d jumped.

  Her galloping pulse pounded in her ears, but Zanna focused. Ignoring the part of her mind yelling that she had approximately 1.4 seconds before splattering over the floor, she hurriedly recalculated, hoping she hadn’t overlooked anything else. There wouldn’t be time for a second chance.

  It held.

  She came to a stop with a jerk and a muffled grunt. And not a second too soon. The ground was only a couple of inches underneath her, enough that she could tap it with her foot. For a moment she hovered there, waiting for her heart to slow down and her stomach to quiet before she called the nitrogen back into her hand. The bedsheet deflated, and she gathered it up in her arms, hurrying as fast as her shaking legs would carry her.

  In order to reach the sitting room with the fireplace, she had to go to the other side of the mansion, which meant passing by the main staircase. In the weird shadows of the northern night, the mansion took on a different face that made Zanna’s flesh prickle. She idled at the bottom of the stairs for a moment, looking up at the locked door of the Variable’s chambers on the second floor. Their conversation that evening echoed in her head, and Zanna told herself it didn’t matter who the woman was. With any luck, Zanna wouldn’t see her again after tonight. Then she shivered once and hurried on.