At last the jet surged down the runway, and Jane glanced out at the tarmac, sliding off beneath the wing. The take-off run was unusually long, she thought. Something to do with the heat of the air, probably. The plane lifted, and banked right before settling on its airway, its invisible track across the sky.

When they were airborne, Jack asked to be taken up to the cockpit; a smiling stewardess complied. When he was gone — out of her sight for the first time in days — Jane closed her eyes. She felt safe here, in the hands of professionals; she felt she could relax.

She sank into the seat, and a small chorus of aches rose from her body…

She slept for a while.

There was a flash, visible even through her closed eyelids, coming from the window to her right. Lightning. She turned and watched absently. There it was again. Roiling black clouds, too distant to be any threat.

Jack wasn’t here, presumably still up in the cockpit.

There was hazy cloud outside the window now.

Sparks flashed across her window, miniature forks, like scale model lightning bolts. St Elmo’s Fire, she thought, discharges from an electrically charged cloud.

She leaned in her seat so she could look forward to the wing.

The whole of the wing was enveloped in a cold glow. St Elmo flashes broke out across the metal, and flecks of light streamed beneath the leading edge like tracer bullets.

She could smell ozone. Puffs of smoke, of some kind, were seeping out of the air conditioning nozzles above her.

The seat belt light came on with a soft chime.

“Jesus,” somebody said. “Look at the engines.”

Jane looked.

The two engines on the wing were illuminated from within, as if by a magnesium flare. Shafts of lights shone forward, like searchlight beams, flickering as the fans turned and strobed the light.

One engine flared more brightly. There was a brief impression of the strobing reducing in pace. Then the electrical fire-light died.

The plane tipped to the right, subtly.

“Jesus…”

There was a thumping noise. The other engines were surging. Dying.

Acrid smoke was curling across the cabin floor. The cabin lights had dimmed, but bright electrical light was shining in through the windows; it was as if the whole wing had caught fire.

The sounds of subdued distress had been replaced by a chatter of concern.

But under the chatter, Jane could detect an eerie silence.

No engine noise. All four must have gone.

And now, beyond the wing, she could see a cloud, an ash tower that looked as if it was reaching to the sky, black and shot through with lightning.

She stood up. A stewardess came to force her down again, but Jane insisted. “Get me to the flight deck. My son’s there.” The stewardess led the way.