I dived down yet again, desperate to try and find Nadia, but it was impossible. I had no choice but to come up for air and follow after Oskar, who had managed to drag himself up onto the abutment. He stood on the concrete, shouting something incoherent towards me as I approached. Soon I felt the riverbed beneath my feet, and I waded towards him.

Suddenly, from out of nowhere, came the sound of rapid fire, and streaks of light flashed overhead. I looked up, seeing it was coming from on top of the bridge.

In the next moment, brilliant artificial light flooded the underside of the bridge, and I squeezed my eyes shut in the same moment that I felt a wave of intense heat sear one side of my body. When I was next able to look, the whole surface of the river was covered in flames, dozens of bodies writhing as they burned.

‘They found us!’ Oskar screamed. ‘They found us!’

Light bloomed again as more napalm fire spread across the water. The wind carried the scent of burning meat towards me, and I leaned over and vomited.

Oskar grabbed hold of my arm and dragged me towards concrete steps that led up to the street level. I followed, seeing both the jeep and the other SUV, the light from its roof-mounted kliegs directed on to the river.

I looked back up at the bridge at the sound of rapid fire. Casey Vishnevsky was up on top, along with the soldiers I had seen back at base camp, all of them wielding rifles and picking off those few bee-brains that were still struggling to escape the blaze.

I reached up to touch the half-coin around my neck and discovered it was gone. I kneeled down, filled with a sudden, frantic despair, peering at the road beneath my feet in case I had lost it at just that moment. I must, I realized, have lost it in the river – most likely while diving to search for Nadia.

‘Where the hell were you?’ I yelled at Casey, my voice cracking. ‘Do you know how long we were out there, trying to find our way back?’

‘Something went wrong,’ Casey yelled back over the din of gunfire, as he paused to reload. In the light of the flames, I saw how exhausted he looked, his face smudged with dirt.

Haden and Winifred, both carrying their own rifles, appeared from the direction of the SUV. ‘We’ll have the bee-brains swarming all over us if we don’t get out of here now,’ said Winifred. She looked over at Oskar, then back to me, the realization slowly dawning in her eyes. ‘Nobody else?’

‘No.’ I shook my head, moisture pricking the corners of my eyes. ‘Just us two.’

‘Goddammit,’ shouted Oskar, slumping to the ground. ‘All these years!’