The staircase was made of thick wooden boards bolted to the bare concrete wall. Valera tested the first step. It held. So she ran down the rest, and burst out into the madness that was consuming the naukograd. She passed other scientists, stumbling out of their labs and offices into the street, and started to sprint towards the school. She outpaced the guards rushing from their posts and parents abandoning their jobs, all running in the same direction, all sharing the same terrifying thought.

The closer she got to the plant, the more damaged the buildings she sped past were. Some had holes blown out of their roofs, some had lost entire walls, exposing all the secret bits of life and work that had been locked up inside them.

She told herself over and over that if the explosion had happened on this side of the plant then the rest of the complex itself might have protected the school from the worst of the blast. That Ledjo and all the other children would be fine—shaken and scared but safe. That any second she’d hear their cries and sobs rise above the shouting of the grown-ups around her. But then she turned a corner and saw in the distance a sight that even her worst nightmares over the last three years had never dared to conjure up.

The cooling tower had collapsed and the plant had been ripped in two, a deep gouge cut through it. And beyond, where the school should have been, was only rubble.

She slowed to a walk, then stopped, frozen, in the middle of the road. She didn’t register the people knocking into her as they ran past. She didn’t notice the hot embers in the air stinging her eyes and burning her nostrils. She only felt a sudden and total emptiness.

Her head told her there was no use rushing towards the gaping void where the school should have been, no point screaming out Ledjo’s name. No one could have survived such a violent explosion. But her heart refused to listen.

After a long, agonising moment she was running again. She clambered through the chasm that had opened up in the middle of the plant. She crushed wood and glass under her feet, climbed over lumps of twisted metal and chunks of brick. It was a gauntlet, and every few metres the carnage was punctured by the raggedy edge of an overall or the blank stare of dead eyes poking up through the rubble.

Then the fabric changed from the dark green of workers’ uniforms to the grey, white and red of children’s. Valera cried out Ledjo’s name, just like all the other parents who were scouring the chaos searching for their babies.