Dec woke to the rhythmic, musical drumbeat of rain on the roof of the shelter—a sound he'd almost forgotten in the long summer drought. At first, he thought he must've been imagining it, that he must've be dreaming, or floating in a desert-dust induced hallucination between life and death. But when he opened his eyes, he realised he wasn't imagining it at all. In the eerie light of early morning, swirled marble by dark, nimbus thunder clouds, the three-and-a-half walled shelter had become three-and-a-quarter walls, the inundation having washed clear the extra rubble from the entrance. Heavy droplets pushed their way through the cracks in the roof to gather in claggy pools on the floor. Dec lay propped against the driest of the three rain-battered walls, head resting on the canvas bags Teegan had brought back from the dump. The back of his pants were soaked through, with what he hoped was water. Somewhere along the line, damp mineral earth smells had replaced the acidic tang of urine.

He licked his chaffed lips, which thirsted despite the rain-sop all around and he turned his head in search of a bottle. Teegan and Rain were at the centre of the room, squatted on either side of a gas-blue flame which was hooked to a space-age trangia by long copper wires. Teegan was holding a needle to Rain's arm, and Rain was letting her pierce the skin down the length of the vein, unflinching as the needle drew pinpricks of blood. They spoke in low tones, audible in the lulls between each cascading downpour. He was about to call out to them, when he heard his name.

"You and Dec ... " Teegan said, massaging a water-soaked mixture of the desert dust into the pinpricks on Rain's forearm. "How did you meet again?"

Rain made a hissing sound through her teeth and Dec noticed her skin had gone bright red wherever it came into contact with the solution. "There was a work relation," she said. "I was interpreting on a delivery to Overlands Trading."

"So, through a mutual colleague or something?" Teegan said.

"Yes, colleague." Rain chewed the word as though attempting to work out the lumps. Then, she winced again as her aggravated skin began to ooze blood.

"I thought you said it was pure chance," Teegan said, seemingly oblivious to the blood. "Like you passed each other on the street."

Rain took a moment to answer. "It was by chance through the colleague."

Dec watched with intrigue. He wouldn't have called his father a 'colleague.' So this is what the Northerner looked and sounded like when she lied? As far as he could tell, it was no different to when she was explaining the origins of her people's folk songs, or when she was telling him to jump off a train.

"How do you know Declan?" Rain asked Teegan, though Dec was certain she knew the answer.

"By chance," Teegan said, gasping when she finally noticed Rain's arm. "Gosh! Sorry! I thought it wouldn't affect you. But this is ridiculous." She dabbed at the blood with the sleeve of her lab coat.

"Maybe this batch is stronger than the last," Rain said.

"Maybe," Teegan replied, reaching into her pocket and pulling out a small torch, which she shone into Rain's eyes. "How are your eyes?"

"Dry," Rain said, squinting against the torchlight. "And the brightness feels like thousands of paper cuts in my irises."

Teegan elicited a low growl of frustration and withdrew another apparatus from her pocket that looked like a spacer attached to an asthma puffer. She held it out. "Breathe through this."

Rain breathed through the mouthpiece and held her breath.

"Dry?" Teegan said after few seconds.

Rain coughed. "Like thousands of bees stinging me in the throat."

Teegan placed the apparatus on the ground with shaking hands. "I can't. This is too dangerous. This batch is definitely stronger than whatever they released in the storm."

"Its fine. Keep going."

"No. We're missing something ... " Teegan picked up the torch again and shone it in Rain's eyes, opening her lids, one-by-one. "It should be obvious. There's a pattern I can't quite ... " she made a motion of snatching something from the air. "Fire seems to be the only thing that kills it. But we can hardly set infected individuals on fire." She scrunched up her face. "It changes colour in sunlight. It has a terminal affect on Southerners, and only minor symptoms on Northerners."

"And some Southerners don't get sick either," Rain added. "You and Declan are unaffected."

Teegan hung her head, and her hands rose to grip the back of her neck. "Think," she muttered to herself. "Think ... " Her breath bumped and hiccuped, and she shook the torch with frustration. "I don't know what's wrong with me! I usually see these things so clearly, but it's like my brain's gone soggy with all this fucking rain."

"You're letting emotion get in the way of instinct," Rain said in a level voice. "Relax. Let it come to you."

"We don't have time!" Teegan snapped, and in an unexpected show of frustration, raised the torch and threw it against the wall, where it stuck, handle first, between a crack in the grout. The globe, miraculously, remained undamaged, and it glowered back at her, harsh and bright. Teegan turned away as though affronted by the glare and Dec saw in her eyes a heavy meniscus of tears on the brink of overflowing. "There are too many variables. I don't know what I'm doing."

The tears overflowed, and instead of talking right through them as she'd done the night before. She dammed them with the backs of her hands while her shoulders shook with each gasping sob.

At first, Rain just sat there, still as a mantis, watching Teegan cry. Then, she leaned in and gathered the shaking blonde into her arms with the surety of a close friend and Teegan responded at first by tensing between sobs, before relaxing into her hold.

They stayed that way for some time, silent, pressed together like a crescent moon around an unclouded sun while over and around them, the rain beat harder, trickled in runnels along the sides of the shelter and down the hill towards the dam. Dec turned away. He couldn't remember the last time he'd hugged someone, or let them hug him.

His gaze wandered back to the glow of the torchlight stuck in the wall and he wondered at the miracle that had landed it there—the combination of force, trajectory and target. He noticed patterns in the lit spores and began to feel ethereally calm, as listless as the dust floating like sand in a dodge tide.

The throbbing in his head subsided, and the swollen heat in his neck cooled with the slowing of his pulse. A globe of an idea formed in his mind, brightening as thread upon thread of filament ideas joined and added to the wattage. Soon, the illumination was so bright, it was almost impossible to ignore the finer details of the pattern—the piece in the puzzle they'd been missing this whole time.

Dec's had to close his eyes to keep the answer from slipping out of his mind. If Northerners were getting sick, but none of them were dying, something was keeping the sickness at bay, preventing it from becoming terminal—something Northerners had, but Southerners were missing out on.

"The sun," Dec croaked, pulling himself into a sitting position so better to hold his head upright and his thoughts from slipping out.

Teegan and Rain jerked their heads towards him.

"Dec? Are you okay?" Teegan began.

Dec croaked on, "Sunlight makes the disease go into remission. That's why no Northerners have died from the illness. Because they're allowed out during the day. The disease lies dormant in their bodies." He paused to take a breath, not wanting to risk ending up ass-skywards again. "If we can get affected Southerners like my mum into the sun, we could save their lives." Another breath. "It's not a cure, but it's—"

"A treatment," Teegan said, breathless as though she was the one who'd just given the marathon explanation.

He nodded.

Their eyes met and a storm cloud of thoughts brewed between them until Teegan's expression split like lightning, her bottom lip stretching into an ugly inside out pout, and her brow folding at the middle as though it had snapped under a great weight. She turned away and Dec saw no more, for Rain rushed at him with a plastic drink bottle and pressed it to his mouth.

"Drink," she said.

Realising now, just how dehydrated he was, he took the bottle and drank deeply, forgetting to breathe between gulps. As the dull ache in his head lifted, Rain replaced the bottle with a packet of biscuits, which he set to eating as though it was the first and last meal of his life.

Rain watched him chew for a moment, before she moved next to Teegan and set the empty bottle beneath a stream of water flowing between a seam in the roof. "Are you okay?" she asked the blonde.

Teegan shrugged. "I should've seen it. It was so simple."

Rain lowered her voice. "You had it. You just needed to relax your mind and not let your emotions get in the way."

Dec studied Rain, and narrowed his eyes. There was something about Rain's reaction to the news of the Desert Dust, or lack of reaction, that gave him pause. It was as though she was completely unsurprised by his revelation that the Desert Sickness could be cured by sunlight. In fact, it was as though—

"You knew all along," he said, the biscuit turning ash dry in his mouth.

Rain said nothing in the flash of lighting that lit the silence between them.

The silence was confirmation enough for Dec, who said, "You let us waste all this time for nothing?" voice rising in competition with the ensuing thunder. He sounded hoarse as a man who'd worn down his throat shouting.

Just like his father.

"The ability to think under pressure is the first thing you must learn as a shadow walker. And the sooner you learn it, the better," Rain said.

"People are dying."

"People die all the time. The difference is, now you're equipped to save the ones that are left." As she said it, she opened Teegan's duffel bag and found the lighter held within. Flicking the spark wheel, she threw it beside the remaining bag of luminite.

Whoomph!

The bag went up in a surge of bright blue flames, the heat of which made Dec's eyelashes curl. All three occupants of the shelter closed their eyes and ducked, the ferocity of the explosion taking them by surprise. If such a small packet of luminite, less than one quart, could create an effect like that, then they could only guess what a whole truckload might do.

Rain spoke first. "Declan, you need you to remember the location of the remaining Desert Dust so we can destroy it."

"Wouldn't it be at Overlands Trading?" Teegan said. "In one of their storage facilities."

Dec ground his teeth. "No. Everything at Overlands is cross docked onwards. It could be anywhere by now."

Rain nodded. "But on the day you were fired, Stanley invited you into his office. He showed to his gantt charts. Somewhere in those charts will be the final destination of those boxes."

Once again, Dec wasn't surprised to find out that Rain knew all about his stint in Stanley's office. He didn't even bother asking how. "We can't break into Overlands," he began. "There's not enough time... and I don't have the key to Stanley's—"

"We don't need to break into Overlands," Rain said. "Everything we need is up here." She tapped her temple. "You just need to remember."