Indra thanks them for arriving underweight. They’re just kids, pupils dilated with expectation. She’s leaning on a Loza rocket, ‘the Super Seeder’, petting its pewter bladder with its payload of silver iodide, winking at us as she repeats lines straight out of the ‘Cloud Couriers Orientation’ document from headquarters.

‘We’re not sentimental about weather. Can’t afford to be,’ she says. ‘It’s not a fairy tale or a mystery. It’s a transaction.’

Are these ones beautiful? We look up from our computer screens and lab benches as the trainees file past. Jarilo’s fingers go limp on the keyboard. Seth and Feng open their mouths like believers kneeling for wafers. Maya lifts her serious chin. Our judgement is dulled by the arid language from HQ: couriers must weigh under forty-five kilograms; couriers must demonstrate upper-quadrant visual spatial acuity and reflexive problem solving; couriers must open an account into which we transfer payments. (Unsaid: the parents, pimps, guardians and gang leaders who actually get those dollars. Not our concern.) Beauty? We’ve lost the heart for it.

The new couriers undress for the weigh-in – standard operating procedure. Their naked flesh, its febrile brightness, swallows the hangar’s available natural light and pulses it back out. Even the usually effulgent Indra, our ballistics expert, seems greyer next to the arrivals.

‘The public veer from anger to despair. And in case you’re wondering, despair is more workable for our purposes,’ she tells them. There’s a bit of a swagger in her walk as she leads them towards the hangar’s empty west quadrant. She’s wearing shiny army boots; her lipstick’s the colour of good bourbon. She hands them thermal skins to don – they have to get used to wearing them. ‘Just south of despair is helplessness. Combine helplessness with awe and we’re in business. Weather mod exploits helplessness. So we have to be reactive, nimble, fast. That’s what we’re paid for. We’re the gods of this shit. We’re invisible.’

The arrivals are silent; the vibe is too serious. Indra cracks a wicked smile.

‘Invisible, but cool. Cloud couriers get some fucked-up air.’

There’s a high-pitched whirr, metal worrying metal, as the retractable roof exposes an expanse of sky, muscling with clouds. Indra clicks open an umbrella with one hand and holds up her remote weather-maker with the other. The rain falls on cue. It falls hard. Even at the hangar’s dry end, we feel pressure systems collide and now it’s the kids, six of them, who have their mouths hanging open.

Meteorologists who become weather modifiers all start the same way. Feng, for instance, was eleven. ‘Skinny,’ he reminds us, as if we’d have a hard time imagining him thus. He lived with his parents near Nansha Beach on Zhujiajian Island. Augusts were insufferable in south-east China. Tourists crowded the shade, sucked on frozen melon Feng sold them, tossing him a few kuai to venture into the sun and snap pictures of the sand sculptures. He slept shirtless. And one night woke to the hut shaking in the dark, the wind drumming sixteenth notes along the walls, seawater and rain spitting at him through an open window. He was flat on the floor when the first wall peeled away and their table pinwheeled through the night air. By the time the bubbling sea met his chin, made his teeth gritty with salt, he was sure he was dead. It was his father’s strong grip yanking him up, dragging him inland against the lifting wind and lashing wet that startled him into living. In the morning, numb and exhausted, they went back to the beach to survey the snapped trees and homes flung like a handful of rice against Mount Baishan. Everything became different for Feng in that moment. He was humbled. He was pissed off. Each of us in our six-person cloud-seeding unit tells Feng’s story as if it were our own. It is our own.

Indra thinks it’s important that the kids fully grasp the technology and understand why pure, irrefutable science is both the product (weather mod) and the spin (Did you see a plane? A contrail? Hear anything? Didn’t think so. If there’s no evidence we were there, we weren’t. A ghost can’t be liable.)

‘The history of weather modification is an epic of lucky incompetence,’ she says. ‘Whether it’s mixing dry-ice shavings with super-cooled water drops in post-World War II Schenectady or using Tupolev Tu-16s to tag cumuli with paint powder for cloud identification, ours is a science that started with whoops. As in “Whoops, did we just make snow? Did we just cause a sky full of clouds to disappear?” ’

Seth feels sorry for the kids when Indra projects a diagram of nucleation on the wall. He makes them each a cup of tea using the propane blaster. All the porcelain mugs have carbon smears on the bottom and the water is too hot. Now they’re shivering proto-couriers with burn blisters on the insides of their lips. And Indra’s still lecturing.

‘They look underfed,’ Jarilo whispers. The trick is not to let the couriers get into your head. For instance, don’t imagine them in the Wasatch Foothills in May. That’s where the pink heat of primrose and the blowy white blossoms of rocky cress can be found. That’s where new recruits could misunderstand an avuncular warmth moving in from the west. And we could misunderstand how ready we were.