Root of Unity

by SL Huang

  “I’m good,” I said.

  “Russell, this ain’t worth risking your life. You can’t be sure—”

  “I’m sure enough,” I said. “But get out and walk about…” I squinted at the payload. Not large, just more than enough to take out the car, with probably even odds on a secondary explosion from the gas tank. “About thirty feet away.” Just to be safe.

  “Russell—”

  “Go,” I said, putting my hand on the car door handle.

  He swore at me again and then eased his door open to slide out. He jogged across the street, head swiveling up and down the road—probably making sure no one else was nearby.

  I took a deep breath and pressed the door handle up until it clicked and released.

  Nothing happened.

  I eased the door out. Slid one foot down over the edge and onto the pavement very, very gently. Then, instead of transferring my weight bit by bit—just in case I’d been wrong about the lack of pressure sensor—I levered myself out of the car all at once, quick and clean, not jarring anything as I launched out into a dive that became a roll that became a run.

  I reached Arthur on the other side of the street, panting.

  “You an idiot,” he said, his voice shaking a little.

  “Of the highest degree,” I answered, looking around for a rock. “We both are, though. We knew they were trying to kill us; we deserved to get motherfucked there.”

  “I was thinking they might leave someone to tail,” said Arthur, an edge to his voice. “Thought they wouldn’t risk sticking around with guns, as they couldn’t know when we’d call in the cops. Ain’t figured on no car bomb, though.”

  Okay, so I was the only idiot. Dammit. I didn’t like it when Arthur made me feel stupid. He wasn’t able to do it often, but more often than most people.

  Arthur pulled out his phone. “Gotta let the authorities know there’s a live bomb on the street here. Think I should probably stay and meet them after all. Make sure no kids come by or nothing.”

  “Oh, I wasn’t planning to leave an active device behind,” I said.

  “Glad you feel that way, but trying to defuse it—it’s way too dangerous. Even experienced techs use robots if they can. The cops—”

  “Who said anything about trying to defuse it?” I said, picking up a smooth stone from the decorative landscaping around an ornamental tree. Small, but small might be even better in this case. “Cover your ears.”

  “Russell—!” Arthur cried, and then he had to duck and throw his hands over his head, because I threw the stone.

  I fastballed it, a line drive straight into the open car door that would give it a perfect reflective angle to bounce off the floorboard and under the seat so it smashed into the mercury tube.

  The fireball was disappointing. It only engulfed the car within the frame, and the gas tank didn’t go. A nice contained explosion. The grenade launcher from earlier had made me think these guys were prone to overkill, but maybe not.

  Or maybe they just knew their explosives. The grenade had been far more powerful than I expected, I remembered. Shit.

  Still, now at least my fingerprints here were conveniently taken care of. I shoved Arthur in the arm. “Come on. Cops coming, remember?”

  He glared at me, and we hustled down the street.

  ♦ ♦ ♦

  “Thought you said we’d play things my way,” Arthur said, when we were settled in another stolen car racing away from the scene. We hadn’t heard sirens behind us, but I was sure that even if Martinez hadn’t made the call, at this point I’d done it for her.

  “Right,” I said. “Sorry. What now?”

  As if on cue, Arthur’s phone buzzed. “Yeah,” he said, putting it on speaker.

  “We saw the explosion,” came Checker’s voice, not entirely steadily. “What the fuck are these guys on—”

  “Checker,” said Arthur.

  He cleared his throat. “The cops just arrived. And bomb squad.”

  “Good,” said Arthur. “What else have you got for us?”

  “You don’t want to talk about the fact that we just saw street cam footage of you two almost being blown to kingdom come? These people are—”

  “We tracked down Professor Halliday’s NSA friend,” cut in Pilar’s voice, as if she could sense Arthur’s growing impatience. “His name’s Dr. Xiaohu Zhang. He’s got a PhD from Berkeley and all the good creds; I think he and Professor Halliday know each other all the way back from then. And he’s been working as a mathematician for the NSA for almost twenty years. As far as we can tell, he’s a good guy. There’s nothing irregular in his bank accounts, he has a wife and three kids, he volunteers planting trees and coaching Little League…pretty much your typical all-American dad.”

  “Who happens to work for a government spy organization that has far too much power and far too little oversight,” put in Checker grumpily.

  “What I’m trying to say is, we don’t think he’s involved,” said Pilar. “Arthur, if you want to—I think this could be a guy you could go to for help.”

  I grimaced. “Even if Zhang’s okay, he’s not going to be the one who calls the shots here. His bosses are going to take it out of his hands.”

  “May I point out that you already called in the police?” said Checker. “The NSA is going to be involved sooner or later, and I remind you that we probably want them involved—and without the delay of the local cops kicking it up to them. They’re going to have a hell of a lot more resources for finding Professor Sonya than the Pasadena PD will, and plus, remember the whole possible-economic-apocalypse? The proof was stolen before we ever made it on the scene, and there’s no putting that genie back in the bottle.”

  Arthur exhaled sharply. “Sonya’s safety is my only concern right now—but you’re right, rather she be in trouble with the Feds than hurt.”

  “If you’re ever coming to rescue me, don’t make those your priorities,” I said.

  Arthur threw me a black look. “Here’s what we’ll do. I can’t give up no chance on this. Where’s Zhang now? At work?”

  “No, he took the day off today,” said Pilar. “He’s chaperoning his daughter’s class trip to the tar pits.”

  “Even better. Pilar, you go talk to him.”

  She hesitated. “Okay.”

  “You’ll be fine,” said Arthur. “Just be honest about what’s going on. Checker’s right, we got to go in whole hog here, ain’t no point in dancing around no more. You can even tell him I’m on my way but I sent you first. Leave Russell and Checker out of it—I want ’em free to keep at this thing without the government coming knocking, so tell ’em it’s just me. But don’t worry about hiding nothing else, got it?”

  “Got it,” said Pilar.

  “I’m going to keep looking into this a little longer before breaking off and joining with the Feds. Checker, you got anything else?”

  “The SUV that tried to kill you has hit police impound,” said Checker.

  Arthur nodded. “I’ll pull some strings, get in to take a look.”

  “While you do that, can I have Cas? I could use her help for the van tracking. Extrapolation is sort of your thing,” Checker added to me.

  “Done,” said Arthur. I wondered if I heard a hint of relief in his voice that he wasn’t going to have to wrangle my differences in method for a while, and then wondered if I was being paranoid. He’d asked me in on this, hadn’t he?

  As a last resort. Because nobody else knew enough math. Not because he wanted me on the job with him.

  “You’re sending Pilar into the lion’s den. You realize that, don’t you?” The accusation spewed out harshly as Arthur hung up. It wasn’t what I wanted to say. “If the NSA thinks she’s involved, or just thinks she’s hiding anything, they could bury her.”

  He scrubbed a hand across his face and didn’t answer.

  Something ugly in me pressed me to keep talking. “Checker, too. He’s not going to have been able to wipe his connection to you enough to hide it
from the NSA. You’re making them both vulnerable.”

  “What do you want from me, Russell?” Instead of snapping at me, his tone was quiet. Desperate. “I don’t know what’s right. Don’t know what to do.”

  Fuck.

  I drove in silence for a few minutes, hating myself.

  “I’ve got a bike near here in a storage unit,” I said finally. A peace offering. “In case you don’t want to steal another car.”

  “What? Yeah.” His spoke as if his mind was a million miles away. “Good. You take it. Ain’t got no license.”

  “Okay.” Neither did I, but then, I didn’t have a real driver’s license, either.

  “Just gotta pray the NSA are the good guys here,” Arthur murmured. “Think they are, but I seen enough corruption to—ain’t got no choice, though.”

  I didn’t agree, but I pressed my lips together. He didn’t want my opinion.

  “Hope Dr. Martinez is all right,” murmured Arthur. “She’s gonna think we’re dead. That the bomb got us.”

  The non sequitur threw me. “So will the bad guys. That’s part of the reason I did it.”

  “And to keep the street safe,” Arthur added absently.

  He always had a higher opinion of me than was warranted, but at this particular moment I wanted to deck him for it. Instead I just didn’t correct him.

  Chapter 6

  I parted ways with Arthur and jetted my sport bike up to Van Nuys, a slightly less glamorous neighborhood in the Valley where people who weren’t movie stars could afford to live. I parked the motorcycle a few blocks from Checker’s house and snuck around the block and through his backyard, just in case there were already eyes on him. Not that it would help if the men in black came knocking. Fucking NSA.

  Checker’s computer cluster and workspace was a converted garage he had affectionately nicknamed “The Hole,” and I pushed open the side entrance to find it a flurry of activity. The space was already crowded, what with the stacks of computer towers and monitors wallpapering it on all sides, and in the small space in the middle Checker was zipping his wheelchair back and forth and throwing tablet computers at Pilar while trying to tell her things she obviously already knew.

  “Just make sure that—”

  “I know!”

  “And if they say—”

  “I know! I’ve got it!” She tucked the tablets into a satchel. “Hi, Cas.” She flashed me a big smile. Pilar was a perpetually friendly, perpetually energetic young woman, curvy and attractive and warm and exactly the type of person most people wanted to be around. In other words, the opposite of me.

  “Kick ass for us with the Feds,” I said. “You’re packing, right?”

  Her dark skin flushed a little, and she reached toward the small of her back self-consciously. “Yeah. It feels funny. Um, you don’t think I’ll have to—”

  “Better to be prepared,” I said. “Just remember, in a gunfight the person who lives is the person who’s more willing to pull the trigger.”

  Pilar made a scrunched-up face like she had just tasted something bad, and Checker cleared his throat and spoke up. “Can I just say—that does not sound like the most, uh, sane approach to gun safety—”

  “Those who refuse to learn to handle firearms aren’t allowed to talk,” I said, crossing my arms.

  “For the last time, guns aren’t my—”

  “Don’t you have somewhere to be?” I said to Pilar, loudly, over Checker’s annoyed squawk.

  “Yes, uh—yes, I gotta go. I’ll be okay,” she added in Checker’s direction. “Good luck to you guys, yeah?” She gave me another smile, not quite as big as the last one, and squeezed by me out the door.

  Checker reordered his various tablets and laptops in her wake, then grabbed the long desktop and pulled his chair over to a large flat screen monitor. “For the last time, I don’t believe in guns, okay?” It was an argument we’d been having for months. “Story, end of.”

  “You’ll start believing real fast the day someone shoots you,” I said. “Where are we?”

  He rolled his eyes and started clattering away at a keyboard as he talked. Skinny and hyper, Checker didn’t sacrifice anything in the way of energy to Pilar, though his was more of the manic and terrifying variety. “You’ve got a workstation there,” he said, pointing to a monitor that had just unblanked itself. “If you can pick up tracking the van, I want to keep working on facial recognition on the goons. Nothing useful’s popped so far, but I still have a lot of avenues to try.”

  “I don’t know how your program things work,” I groused, plopping down in the chair Pilar had vacated.

  “Really? Really? You with the superpowered math brain who can figure out the abstraction behind an undocumented program in a night can’t handle doing calculations via a graphical user interface? Quit whining and do it.” He pointed at another monitor. “Go forth and constraint propagate. This is for Arthur, remember.”

  He was right, dammit—I could be pissy later. I told myself it must be the vestiges of the concussion that were still making me grumpy. I rubbed my eyes and took a glance at the way his program was set up—I got a sense of the mathematics right away, the calculus of moving objects, the grid of cameras and other surveillance he could hack into, the ever-expanding search algorithm and, yes, constraint propagation. I fiddled with it for about forty seconds, plugging in different values, and narrowed down his heuristic empirically until the bounds almost touched.

  “You can do a lot better,” I said. “Faster for more likely inputs. If you make it probabilistic—”

  “That’s why I wanted you here,” he interrupted. “Just do it. After this is over, you can help me reprogram the search. I’ll pay you in tequila.”

  We started working. Checker was a bundle of nerves, tapping a pencil against whatever monitor he was at when his fingers weren’t going a mile a minute on the keyboard, and checking his phone every five minutes.

  “Arthur has your number,” I said. “And Pilar hasn’t even gotten there yet.”

  “I know, but what if—” He sighed and took his glasses off, tossing them next to the keyboard in frustration and going back to typing.

  Hell if I knew what he wanted from me. Just like Arthur.

  I kept working, mixing in manual checks of the maps in the area and pulling cherry-picked data from the program’s algorithms to figure into my calculations.

  “Arthur’s lost a lot of people,” Checker said suddenly, a few minutes later. “I’ll be damned if he loses one more, okay?”

  “I didn’t say anything,” I bit out. “I’m helping, aren’t I?”

  “I know. I know. I’m sorry.”

  But Arthur hadn’t thought I’d be willing to jump in, either. He’d probably only forced himself to call me because he was willing to go to hell and back for this woman. To try everything.

  Even me.

  “What is it with him and Halliday, anyway?” I groused.

  “What do you mean?” asked Checker. “He’d do the same for you, or me, or Pilar, or—or anyone else close to him. You know that.”

  I sincerely doubted the part about me. I rubbed my eyes again and reapplied myself to the computer, hating everyone. My head still throbbed.

  Checker stopped typing for a moment and leaned back. “They were best friends since they were about five, okay? Until, uh, a few years ago. They got each other through a lot, as kids. At least from my understanding of it.”

  “Oh, best friends,” I said snidely. “Is that what they’re calling it?”

  “What are you, a thirteen-year-old?” Checker snorted and went back to his keyboard. “I know I’m the last person you expect to say this, but not everything is about sex. Besides, Arthur’s had himself figured out since he was about ten. I’d be very surprised if anything ever happened between them.”

  I’d never heard of Sonya Halliday before last night, and here was Checker with her whole life’s history. Everyone else had known what was going on here before Arthur had pulled me in for
dumb computational comprehension and hadn't even trusted me to agree to be that.

  I stabbed at the keyboard.

  “Hey,” said Checker. “This might be the most inappropriate time to ask this ever, but are you okay?”

  I kept stabbing. “Fine. It’s just a concussion.”

  “I don’t mean now, although I’m glad to hear a concussion is included in your definition of ‘fine.’ I meant in general. Until today I hadn’t seen you in weeks. You’ve been ignoring all my messages—”

  I tried to shrug him off. “I was on the job.”

  “One, that’s never stopped you from mocking me through text before, and two, no, you haven’t been, at least not the whole time. I checked.”

  “You were tracking me?” I put a little righteous anger into the words, even though I’d already figured he had been.

  “Of course I was; I wanted to make sure you weren’t dead! What happened to coming over here to get your tequila on? There’s another season of The X-Files that’s begging us to play drinking games to it.”

  “I didn’t feel like company,” I said, still concentrating on my screen. And maybe I’d been sick of trying to live up to his and Arthur’s standards, sick of trying so hard to be the human being they saw me as. Sick of failing at it.

  “I get that,” said Checker, oblivious. “You just seem—I know, I know, concussion. But…you know if you need anything, that I’m—I mean, you can…right?”

  I was saved from answering, thank Christ, by hitting the jackpot. “Hey. I found the van.”

  Checker was at my shoulder immediately. “Where?”

  I didn’t know how to do any sort of fancy computer highlighting, so I traced a rough circle against the monitor with my finger, ignoring it when Checker cringed. He didn’t like people touching his screens. “It disappeared into this area almost half an hour ago and hasn’t come out.”

  “Are you sure? There’s no way it could’ve—?”

  I glared at him, and he shut up.

  “Okay, I get it, you’re sure. Two possibilities, then: their base is in the zone, or they switched vehicles. Can you run the security footage on the border of your zone forward and—never mind, I’ll do it,” he said hastily, at my blank look. He started punching keys. “You know, you could learn to do this stuff in about three seconds if you gave half a crap.”