They quickly settle into a routine. On Saturdays and Sundays, Pidge meets Keith at the commuter lot early in the morning and follows him out to the shack. They set up the equipment and she stays until Kerberos falls below the horizon at nightfall, working on her homework assignments in between honing the receiver's alignment routine and filtering. The alignment is the hard part - she doesn't have an astronomical radio dish at her disposal, and there's nothing to tell her when she's pointed at the right part of the sky. All she can do is test her tracking routines on well-known radio signals (low Earth orbit satellites and the lunar relays are some of her first targets), and hope that her trajectory calculations for Kerberos are right. It's boring, finicky work, but each pass makes it a little more accurate, a little more stable.
At first, Keith alternates between loitering curiously on the porch and abrupt excursions to work on his bike or circle out into the nearby desert, like he doesn't know what to do with her presence. By the end of the second weekend, though, he claims a spot a little ways away from her and parks himself there for most of the day. Sometimes he brings out an ancient toolbox and something to work on. It's mostly small engines - old lawnmower motors, washing machine pumps clogged with socks, cleaning droids with their contacts covered in dog hair. He takes them apart and cleans their pieces, swaps parts until they work again. Other times, he covers the pages of a cheap notebook with rambling geometric designs. During the midday hours he dozes slumped up against one of the porch's supports, arms crossed and eyes slitted closed against the sun while she eats her lunch.
Normally, she wouldn't appreciate the company. She doesn't like people hovering over her while she works. But Keith's presence is weirdly comfortable. There's no expectation that she devote her attention to him - they're just two people sharing space while they work. It takes a lot of the pressure off, and she finds herself talking to him while she works sometimes. At first it's just griping about the latest problem with the alignment and the troubles she's going through to fix it. But little by little, other things start to slip in. The lab she's having to redo because some kid in her electronics section didn't read the component power ratings and started a fire. The 8AM operations course that nobody - including the instructor - is awake for. The dumb internet slapfight she's having with one of the weird desert sounds conspiracy theorists. It's not like her to talk so much to someone she doesn't know well, and part of her is a little freaked out, but she can't seem to stop. She hasn't really talked to anyone in weeks, not since she left home, and Keith is the only person on the planet who knows what she's doing at the Garrison.
It hits her right between the eyes late one Sunday, surprised by a dull pang in her chest as she packs up to head back to the Garrison. She's lonely. Keith notices her pause and straightens up from helping her pack the saddlebags.
He frowns. "Everything okay?"
She shakes her head. "Yeah. Sorry."
He watches her seriously for a second, eyes searching her face like he's about to say something, before he shifts uncomfortably and turns back to loading the equipment. She bites her lip and thinks maybe he's lonely too.
After that, she starts making a conscious effort to ask him questions. She's pretty bad at it, but Keith is pretty bad at answering so it evens out. She learns that the used appliance shop at the corner of 3rd and South pays cash for the small engine repairs he does. The fossils on the step come from a roadcut a few miles south that he visits sometimes. He's been watching a family of coyotes from a distance for the last month and he's named all the snakes that sun themselves on the rocks in back of the shack.
She's certain that he lives in the shack by now, but he never says it, and she doesn't ask. He never mentions other people.
Gradually, he begins to ask her questions and offer occasional comments. He wants to know whether Instructor Warner is teaching Introductory Navigation again. He's genuinely curious about what she's doing with the receiver, and never seems bored or put off by her explanations, even if she has to explain the jargon to him. His opinion on her conspiracy theorist internet nemesis is so bluntly devastating that she messages it to him on the spot and they wind up wasting the next hour in a satisfyingly petty teardown of conspiracy theories at large.
(They probably count as conspiracy theorists themselves now, but neither is willing to cross that bridge.)
The trips out to the shack quickly become the bright spot in her routine. During the week, she finds herself sometimes turning to say something to Keith, always a little startled not to see him there. It's not too surprising after she thinks about it - she's not really talking with anyone else these days. The desert even starts bleeding into her subconscious. Sometimes she'll catch a glimpse of the shack on the horizon or find herself gunning the bike down the highway towards the exit in the middle of her usual muddled, hectic dreams. It always leaves her feeling a little strange and disconnected when she wakes, but it's a relief from the dismal loop of classes and her mother and Kerberos that her mind normally runs when she sleeps.
Today, she's got the receiver locked on what she thinks is one of the old Mars orbiters. It's the longest the alignment has held so far, and she's holding her breath watching the data tick in, hoping it keeps pace with the Earth's rotation this time. Keith's leaning a shoulder against one of the porch supports, watching her out the side of his eye, his latest repair project halfway put together next to him. It's getting to be the time of day when he shuts down. The decisive click of her final entry draws his attention.
"Still holding?" he asks.
"So far so good." She sits back down and stretches her hands out, knuckles cracking. "Just gotta wait."
He starts to say something, and then freezes in place. A heartbeat later, the hair goes up on the back of her neck and she hears it too. The Knell's long, uncanny roar rings through her bones like thunder. She's heard it - or its echo - occasionally at the Garrison, muffled and half-imagined, but up close it goes through her like a shock of ice down her spine. She forgets to breathe for a second.
Keith's up on his feet in an flash and she scrambles to follow suit. He darts into the shack and comes out with something clutched in his hand. He shoves it into a pocket and pauses a moment at the door, hand hovering over his chest. He shifts on his heels, orienting himself eastwards like there's a line hooked under his sternum tugging him around. Without thinking about it, she finds herself rotating to face the same direction. She frowns and puts a hand to her own chest. For a second, she's almost convinced she can feel something pulling at her, but it's gone in an instant.
Keith rocks on his feet like he's hit a physical stop, and then turns himself at a forty-five degree angle and hops off the porch. He catches her eye as he does it, and she knows he's going to chase after it. Without needing an invitation, Pidge follows.
They tramp out into the desert until the shack is just a blip on the horizon behind them. The Knell has faded by now, but Keith seems to know where he's headed, and eventually they arrive at a tower of flat, craggy rocks. Keith does something disgustingly athletic that has him up and over its lowest ledge like it's nothing. Show-off, she thinks, scowling up at him.
Keith pauses and blinks down at her. "Sorry," he says awkwardly, before going down on his belly to dangle a hand over the edge. "Here."
She shoots him a dirty look, but jumps a little to catch at his fingers. His hand clamps over hers and she braces her feet on the rock, and between them, she clambers up too. The rest of the climb is easier, and they make it to the top in short order. From up here, the desert seems to stretch out endlessly, heat shimmer bleeding the ground out into the sky. Keith turns in a slow circle before coming to a dead halt facing northeast. His hand is raised over his chest again.
She eyes him curiously. "Are you still hearing it?"
He starts a little and yanks his hand down. "Don't really hear it," he says after a moment. "Can still feel something, though."
"Huh." She bites her lip thoughtfully.
Keith steadfastly avoids her eyes, staring out at the horizon. After a second, he digs in his pocket and draws out a flat, rectangular shape, holding it out straight and level in front of him. She leans over and sees that it's a cheap analog compass, the hard plastic scuffed and marked with sharpie at the edges. He jerks his head over towards a point to their left. "Took a heading from over there last time."
She squints into the distance and can make out another rise in the landscape. "So you can triangulate it? That's smart."
He ducks his head down to look at the compass, hair falling over his eyes. "Too far away to follow it directly."
She hums and pulls out her phone. "Here," she says. "What's your heading?"
"Sixty-seven degrees."
She notes it down and frowns. "We should get-"
"-multiple readings. I know." He shakes his head and blinks. She raises an eyebrow at him, and after a second he shrugs. "Must have learned something from watching you spend all that time realigning."
She snorts. "Yeah, all right. Rub it in, why don't you." She thinks a minute. "If we really want to do it right, we should take them blind, so we know you're not subconsciously picking up on visual landmarks." She hesitates. "Uh. You could close your eyes and I could spin you around a few times?"
Her stomach clenches almost as soon as the words leave her mouth. What if she spins him around and he winds up pointing in a different direction every time? What if they've been fooling themselves, following a sound that doesn't really exist? What if Keith has just been out here too long, going crazy by himself in the desert?
The feeling subsides almost as quickly as it came, and she shakes off a sense of unease. It's not like her to second-guess herself. Keith draws a breath next to her and she wonders if his thoughts are running along similar lines. "Okay," he says.
She eyes him, still unsettled. "We're both hearing it, right? There's got to be something out there." She's not sure which of them she's trying to convince.
"Let's just get it over with."
A couple of minutes later, she's standing on top of a rock facing Keith.
"This feels stupid," he grumbles.
"Quit whining," she tells him. "Ready?"
He rolls his eyes and then squeezes them shut. "Ready."
She brings her hands gingerly down on his shoulders. He spooks a bit at the touch, but lets her spin him around for close to a minute, until he wobbles a little in his tracks.
"Okay, go!"
Slowly, he drifts to a halt, eyes still shut, compass held in front of him. She leans over and whistles. "Sixty-eight degrees." She notes it down in her phone.
They repeat the experiment a few more times. Each time, Keith comes within a degree or two of his sixty-seven degree heading. "Well, you're certainly locked onto something," she tells him, and pretends not to notice the relieved breath he lets out.
They trek back to the shack and she settles back down on the porch to check the receiver's progress. Keith disappears inside and comes back out clutching an ancient corkboard, a spool of twine, and a mason jar full of mismatched pushpins. He sits down in his usual spot and she cranes her head over to look. Pinned to the board is a yellowing topographical map. A pair of pushpins anchors a strand of twine stretching across the geography like a ray of light.
She makes a delighted gasp. "Is that-"
Keith gives her a sour look. "It is not."
"It is."
"No."
"I know a conspiracy board when I see one."
Keith scoffs and sticks another pin into the board, a little ways away from the first. "That's where we just were." He cuts a length of twine with the knife he keeps on his belt and loops it around the pin. He lays the map flat on the porch and painstakingly lines up its north with the compass. Carefully, he pins the twine stretching out across the map at the sixty-five degree mark, the minimum of the headings they've taken. He cuts another length of twine and repeats the process at their maximum of sixty-eight degrees. Together, they cut a narrow arc stretching out through the desert pointing away from the city. The previous string intersects it at an obtuse angle. Keith scowls at it and flicks at its pin. "Going to have to redo that one and get a range."
He stares down at the map for another few seconds. "Thanks. For the range idea." He pauses, grimaces. "And for spinning me around."
She grins. "Anytime." Keith huffs, but there's no bite to it.
Silence settles down on them while Pidge logs the last data run and punches in a new set of calibration constants. Keith picks up the corkboard and disappears back into the shack with it. When he comes out again, he takes up his previous place leaning against a support, his eyes starting to drift closed again in the midday light. Pidge glances at the angle of the sun slanting across the porch and digs in her backpack for her lunchbox. The icepack inside is mostly liquid by now, but the foil-wrapped sandwiches are still thankfully cool. She takes the one closest and then hesitates a second before picking up the other and shoving it in Keith's direction.
"Here. Hope you like turkey."
He rouses and stares down at it like he's never seen a sandwich before. "What?"
"Just take it. It's weird eating by myself."
He eyes her for a long moment before his mouth snaps shut and he cautiously reaches out for it. Carefully, he unwraps it and opens it up to begin methodically picking out all the tomatoes and cheese. He catches her eye and flushes. "Can't eat tomatoes. Or dairy."
"That sucks," she pronounces. "What can you eat? Besides turkey and bread."
He squints. "Bell peppers…?"
She mentally marks that down as a 'maybe'. Given that she hasn't actually seen him eat anything up until now, maybe she shouldn't be surprised. "Okay. I'll get you something with those next time. I'll grab a menu so you can pick what you want."
He's quiet for a second. "I'll pay you back."
She waves a hand. "It's fine." She's not sure what he makes under the table from his repairs, but it can't be much. She's not completely sure he's not just squatting out here. She's not exactly rolling in cash either, but buying deli sandwiches is far from the worst thing she's done with her college fund at this point.
Keith's jaw sets mulishly. "I'm not a charity case."
She scowls. "It's not-" Something pricks at her hindbrain, a familiar nettling sting of hurt and stubborn independence. She bites back the words and tries again. "Look, you're letting me set up out here. I owe you." She blows out a breath. "You could have just kicked me out or blown my cover if you wanted. The least I can do is bring lunch."
His shoulders tighten, and he glances away. "I wouldn't do that." A long moment passes before some of the tension finally drains out of his spine. "Thanks," he says at last.
"Mmph," she replies through a mouthful of sandwich. Out of the corner of her eye, she watches him sigh and finally relax into a boneless lean against the porch support.
They eat quietly for a while and Pidge finds her thoughts wandering back to the Knell. She's more and more convinced that Keith is right, that it isn't really a sound. In the muddle of their hurried exit from the porch, she distinctly remembers the creak of the shack door and the hollow thunk of their footsteps on the floorboards, clear despite the Knell's apparent volume. It doesn't echo the way it should against the rocks, and for all that it feels like it has a pitch, she can't find it, humming up and down a scale under her breath. And there's something different about the way Keith experiences it from the way she does - he'd followed whatever direction it gave him out into the desert long after she'd stopped hearing it. She thinks about that brief phantom tug under her breastbone and frowns thoughtfully.
"I can feel it all the time," Keith says abruptly into the silence. His eyes are pinned straight out on the horizon line.
She starts at the interruption and a chill runs up her spine. "Spooky," she mutters to herself.
Keith hauls himself upright and seems to shake himself out of his half-daze. "The Knell, I mean."
She firmly quashes the sense of weirdness prickling at her. They just spent most of an hour chasing the Knell down. It's not surprising they're both still thinking about it. "'All the time?'" she asks carefully.
A couple of seconds pass before he replies. "Yeah. Stronger when you can actually hear it." He frowns, fingers tapping restlessly on the floorboards. "Or, I don't know. Not stronger, exactly. Clearer. More distinct."
"I think I felt it too for a second. Like a pull in your chest, right?"
"Exactly." He lets out a breath.
She can't stop an electric thrill of excitement going through her. She's never really doubted that the Knell's real, but actually following it brings it starkly into focus. There's something out there in the desert, somewhere in that arc of land on Keith's map. "What do you think it is?" she asks.
"Up until you heard it, I thought it was just me," he replies bluntly.
"Definitely not just you." She shakes her head. "I mean, what is it? Why's it sitting out here putting out... vibes, or brainwaves, or whatever it is? What's it doing out here? What does it want?"
Keith hesitates and then shifts uncomfortably. "I always thought it sounded lonely."
Lonely. It stops her short. There is something lonely about the Knell and the way it saturates the space, drowning everything else out. Nothing else seems real around it. It boils the world down to just her and Keith, looking for the footprints of people who are never coming back, following a sound that no one else can hear. "I guess it does," she says after a second. "Maybe it just wants company." She breathes out and pushes her glasses up on her nose, shoves the ache back down. "Or maybe," she says firmly and with a certain degree of bloodthirsty satisfaction, "it's just trying to lure us in. Like an anglerfish."
Keith thinks about that for a few seconds. Then he casts her a sly look out the side of his eye. "Spoken like a true conspiracy theorist."
She sputters and throws her sandwich wrapper at him.