The reactors Titans use burn traveling-wave lithium deuteride cores: smaller and more elegant than their older pure plutonium and uranium counterparts; compact suns the size of grand pianos tucked into ribcages of tungsten, clothed in titanium alloy. The lithium deuteride moderates the fissile uranium-plutonium lifeblood—slows down the burn by engaging errant neutrons in a perpetual gavotte, keeps 238 and 235 alike quivering on the edge of shattering. It is a delicate balance.

  The day your sister died her metal heart slowed before it sped up: there was a pause, a breath held, in which the propagating shockwave from the epicenter of her suicide reached the rest of all those shivering atoms and broke them apart. The lithium deuteride did its job—held everything together—kept it from shattering a moment longer—and that is what let her unleash the sun underwater; that is what gave the bomb she’d made of her own reactor the extra sliver of time it needed to reach its fullest potential.

  Thermonuclear weapons detonate at ten times the temperature of the center of the sun in your sky.

  At this temperature it was, perhaps, the tons of metal between my brain and my heart that saved me; the water too, and the extremophile bioclad they wrap every helmmaster in. Still—tungsten melts at five orders of magnitude under the heat at the core of that reactor; nickel steel half that; ceramics less; aramid fiber, hardly anything.

  Your sister was gone before I could count it. She was ash before the synapse that had commanded me could finish firing. So too the tungsten ribcage, the steel joints, the ceramic heat guards, the suit—the cradle, the harness, the helmet.

  You know this, of course. You’ve done the math over and over since you got the news that bright sunny Thursday morning six years ago. Though you were no engineer you knew: she didn’t suffer when she died. It did not take long enough for her to know it had happened at all.

  And yet. And yet.

  -

  You wake before I can alarm you and you lie there in the sweating darkness, staring up at the ceiling of your dorm.

  Showering is perfunctory; so is dressing. You don’t see the courtyard with fake trees at all or the stairs or the doors to the gym on 52. Your mind is somewhere out there, a thousand feet below, in the murk between the ruins of Ma Wan and Discovery Bay.

  You’re early. At the door you set down your kit and canteen and trot onto the track. Is Carol there yet? Do you want her to be? Better not think about it. You slouch into a bench in the middle and work the nails of each of your hands absently into the webbing of the other, trying to calm your already racing heart.

  The door opens. You jump. Three long shadows lance your own.

  “Oh shit,” says the biggest one, Gutierrez by the way she moves, and waves. “Hey, new girl!” Great; you want to sink into your own skin and never emerge again. “You know it’s bad manners to beat me here, right?”

  No way that’s a rule. Is it? Lau’s next to Gutierrez, half-shadowed in the pre-dawn blue-gray; you meet her eyes and she stares back flatly. Abruptly you wonder: Did she get along with Ray? Does she hate you too?

  Well, Gutierrez is coming right for you and there’s really no avoiding it, so you force a smile—more of a grimace—and do your best to brace for impact. But then the third shadow says, “Easy, Trace,” and you could thank God right now for all that you’re a nonbeliever: “You’re scaring the poor girl. Give her room to breathe.”

  You squint. You don’t remember this voice from yesterday’s comms: cool-toned, a little British. She’s a pilot, of course, if the red-blue-white-black uniform over one arm wasn’t evidence; tall, even leaner than Carol, a glint of gold in her pile of long, neat dark locs. Walz? Dare?

  “Where are my manners?” says Gutierrez. She plops down beside you and gestures broadly. “Debrah’s with Venky. Captain of the Fishhawk. And you know Shirley from yesterday—”

  “Call me Lau,” says Lau, clipped.

  “God, Shirley, is that stick up your ass what Shi found so charming? Because I sure do,” says Gutierrez brightly. “Anyways, seriously, you’re gonna have to make it up for me for beating me here. Can’t let Chang see the newbie making a bad example of me. Speaking of which—”

  “Here.” You startle. You don’t see Carol; her voice floats toward you from somewhere by the door.

  “Great!” Gutierrez claps. “Ladies, you know I’d love to spend longer shooting the shit—”

  “Hearing yourself talk,” says Lau.

  “Potato, potato. Debs, tell Venky I love her very much and I’m sorry for stealing Holly last night. Half sorry,” Gutierrez amends. “That ass makes up for anything.”

  Debrah chuckles. “Don’t think Yen’s gonna like that,” she says. “You ready for another beatdown? So soon?”

  “Oh, please,” says Gutierrez, “Em gave me a love tap. We’re friends.”

  No the fuck you’re not, but how are you supposed to say that in the face of big dumb grinning Gutierrez and her meaty paws and her cronies, who are senior to you in rank if not function? Better just let her tire herself out.

  Debrah shrugs. “Sure.” She looks over at you. “Hey,” she says, “don’t be afraid to give her another love tap if she starts running her mouth, yeah?”

  Gutierrez pouts, big and dramatic. “Go,” she says. “Just go. Get out. You’re breaking my heart, Dare.”

  Debrah just grins. “That’s what I’m for,” she says. “See you in the thunderdome, kids.”

  Lau follows her out. Gutierrez watches them go. So do you.

  The narrative has been taken without authorization; if you see it on Amazon, report the incident.

  “Fucking buzzkills,” she sighs. “Am I right? Okay, let’s get this shit over with.”

  Great! Anything but drawing this embarrassment out longer than it has to be.

  A fool, you, to think it should be so easy. Only takes ten minutes this time before you’re a sweating, snotty mess. Of course; why did you think it would be any easier than yesterday? But you’re determined to make a better showing of it than last morning; you can’t be weak, not after puking in front of Ray’s Titan and passing out. And Gutierrez, damn her long stride, is already a hundred paces in front of you.

  Doggedly you screw your jaw shut and force yourself to keep going. Left, right, left again—like making yourself stay awake in the cold of the cradle without a suit. Come on, Em, you can do this. Knives in your lungs. Fuck you wish you’d gone on more bike rides back in the Bay.

  (Carol is somewhere in the darkness, watching you fall apart, surely. She says nothing. You don’t know if silence is better or worse than the alternative.)

  Gutierrez notices the second time she passes you. You wish she hadn’t. She breaks her stride, trots over and slows till she’s matching your limping pace. “Need a break?” It’s insulting, sure, but the way she says it sounds honest, and so’s her face, what you can see of it in between your bangs and the sweat in your eyes. You don’t get it.

  “Nah,” you manage, “I’m good.”

  She snorts. “Hey, Carol,” she shouts. “Don’t tell Meng we’re taking five or I’ll put toothpaste in your lube bottle.” No answer. You’ll take that as a Sure.

  Gutierrez all but manhandles you to the middle of the track, and you’re too tired to really fight back anyway; at best you manage a kind of halfhearted writhing. She could probably fireman carry you if she wanted to, so you guess you should be grateful she doesn’t. There she props you up against a bench and—oh, isn’t this a turn of events—holds her canteen out to you expectantly. In your pride you refuse to take it.

  “Come on,” she says, shoving it at you. “Nobody’s gonna know you’re a huge dork when we’re all a mile deep. Seriously, Kanagawa, who are you trying to impress? Just take a fucking sip.”

  So you do. You feel like a fucking baby but God the water tastes good and fuck, you needed this. Why didn’t you fill yours before you came up here? Well, you’ll learn the hard way, then. For now you drink, and Gutierrez smirks at you, and you try not to get angry at that. Whatever she’s hungover on today, you almost wish you were too so maybe the headache would distract you from the indignity of it all. (And surely Chang’s watching all this go down. You’re frankly relieved you can’t make her figure out.)

  “Good?” She puts her hand out at last, looks at you eyebrows raised. Sheepishly you hand it back. “Let’s take it easy, Flabs,” she says. “Don’t want you puking again when we just polished this place up last night. I’ll sandbag so you can keep up.”

  “Meng never said anything about having to match pace,” you say, trying and failing hard to be biting.

  Gutierrez grins, all canines. “Meng doesn’t say a lot of shit,” she says, “doesn’t mean we don’t still have to do it. Look, I’m trying to be nice. Say thank you.”

  “Thanks, Gutierrez,” you mumble.

  “Blech! Please. Call me Trace. Gutierrez makes me sound like my mom, and that makes me want to throw up.” She gets up, offers you a hand; you don’t take it, get to your feet on your own—shakily, but you do it. No snarky comment from her. Wow. Maybe she really is trying to be nice.

  On the track, true to her word, she hangs back and jogs slowly by your side. You’d hoped she might let you run in blessed silence. No such luck. As you round the curve she says, “I ride Ghost Eater. You might’ve seen us on the news. Busan? Hydra Meg?”

  You don’t remember seeing a Meg on prime-time that fits that bill. You don’t mention that. In the lightening glow from the windows, her smile’s big and blocky and almost a little unsure—charming for someone so big, who looks like she could eat you in one bite—and you’d rather not get eaten, so.

  Instead, you keep your head down and think about easier things, things you know, things that keep the taste of ozone out of your mouth and the buzz out of your hands and gut. Ghost Eater’s an offense unit, big and brawny, almost as big as a defense, with rows of bulky serrated off-gas panels on both shoulders, unique among its kind because they deprecated the design right after for how much energy those elements guzzled. One giant headlamp—standard. Cockpit shaped not unlike a horseshoe crab, but way more threatening. Like a…really fucked-up horseshoe crab. (Yeah, you can work on that one.)

  And who’s defense for that? You go over the faces you’d glimpsed last night, try to match them to the grainy VHS press releases of your childhood. Some of the girls look older, more worn; Shi is dead, and you can’t tell if Debrah’s the replacement or if that’s Walz, who might’ve gotten married, since you don’t remember her surname in the lineup, although her voice seems familiar enough. Kanagawa is dead, too. Obviously.

  Venkatesh, Gutierrez, Tagouri, Chang—Walz; Dare, AKA Debrah, AKA Debs, the girl with the locs; Lau, who’s only recognizable to you by the shape of her eyes and mouth—gone are the childlike roundness and thick black hair of her youth, supplanted by knife-cheeks and an austere buzz, and Sanskrit tattoos climb up her neck now. Buddhist? A monk? Out here, in the middle of combat? You’ve never heard of a monk with tattoos, not like these, but then again you’ve never seen a lot of things on Kowloon Base before (the Barracuda in person, techs doing spitting challenges past the railing of the observation deck when Tagouri brought you up there, fermented soy paste in the dining hall, Carol), so.

  “Been an hour.” That’s Carol, somewhere in the middle of the track.

  “Thank fuck!” Gutierrez huffs noisily, trots to the side of the track. She’s looking back at you; the whites of her eyes gleam. “Fresh Meat! You coming?”

  Slick with sweat, still half-bent on the boundary line, you manage, “Coming where?”

  Gutierrez rolls her eyes. “Breakfast. Obviously,” she says, grabbing a towel from her duffel to sling over her shoulders. “Unless you’re as anorexic as you look.”

  You’re not letting that one go without a fight. “What,” you say, “afraid I’ll puke on you again?”

  Hey, not much of a defense, but Gutierrez laughs anyway. “Nah,” she says, chafing vigorously at her obnoxious bird’s nest of hair with the towel. “You need more meat on your bones, is all. Though speaking of puking: Never pull that shit from yesterday again.” She turns serious. “You know you got us all in trouble with Meng, right?”

  You bristle. She holds up a hand. “Nope,” she says, “shut up and listen. When Holly pulls her friendship-is-magic bullshit and says we’re a team, she means we’re a team. You fuck up, we all do. Goes for any of us.”

  “Right,” you mumble. “But it isn’t my fault that—”

  “Your fuck-up is our fuck-up,” she says. “Two-way street. And you know what else? We don’t read minds.” And she looks you dead in the eye. You find yourself unable to retort. “It’s not just every sword for her shield. Most of us aren’t in your head. Anything wrong, you talk.”

  Maybe I don’t want to tell you—is what you want to say, but you bite your lip. You’re smart enough to know she’s right. So you say, “Sorry. Yeah. I get it,” and there’s that stupid grin, back from the abyss.

  “Great! Didn’t feel like putting toothpaste in your lube too.” She stands, walks over, and offers you a hand. “Yen’s dying to know what you look like without puke on you. Shall we?”

  What, sign yourself up for inevitably more suffering? What did Debrah call it again? Right. The thunderdome. You don’t bother to search for Carol in the gloaming this time. In you go.