The marketplace grew darker still as the storm took hold. Sheet lightning and the cannonball rumble of thunder warred angrily in the clouds overhead. Rain drummed on the roofs of houses and pummelled the earth-packed streets, until puddles turned to streams that grew into torrents. The deluge became so great that it was as if the heavens themselves wept for Akiko’s loss.

Jack hung his head, the pillory holding his body at an unnatural and excruciating angle. When, after a time, his neck had become stiff and sore, he forced himself to look up and stretch out his aching back. The rain having eased slightly, he spied through the evening gloom four figures riding up the road towards the town gate. Their pace was slow yet measured, like a funeral procession, their bearing sinister and menacing, a clear warning to anyone to keep out of their way.

Nevertheless, the gatekeeper emerged from his shelter to challenge the late-night visitors. Jack watched as he held aloft a fiery torch and, in the glow of its guttering flame, rivulets of rain gleamed on the riders’ waxed black cloaks, and – briefly – a ghostly vision of four white, beaked masks appeared. The gatekeeper stood stock-still, apparently frozen with fear. Then he dropped the torch and turned to run, but, following a flash of steel, he slumped face-first in the mud, beside the torch’s dying flame.

Jack blinked away the rain in his eyes, uncertain of what he’d just seen. The movement had been almost too fast to catch in the darkness.

‘Did you see that?’ he whispered to Yori.

‘What?’ said Yori, uncurling himself and peering into the gloom.

‘I thought I caught a glimpse of a sword,’ Jack explained breathlessly. ‘A samurai sword.’

Yori stared into the rain, trying to make out the four horsemen riding up the street towards them. ‘I don’t see any samurai sword,’ he replied timorously, ‘but I do see four plague doctors!’

A sudden flash of lightning scorched the sky, revealing in all their morbid horror the riders’ birdlike masks and black hats and cloaks. Jack recalled the courtesy-man’s warning of plague doctors terrorizing London and felt again the paralysing fear from his childhood. Harold had been right to describe them as the horsemen of the Apocalypse: their unearthly appearance struck terror into his heart.

The four figures pulled their horses up at the edge of the marketplace. They looked cautiously around until their cold, dead gaze fell upon Jack and Yori imprisoned in the pillory and stocks. Dismounting, they began to approach.

That was when Jack’s survival instinct overcame his crippling grief. He started pulling on his arms and straining with all his might against the pillory. ‘We’ve got to get out of here, Yori … now!’ he hissed.

Yori, for his part, had begun tugging at his ankles, in vain. ‘But how?’

‘Use kiai-jutsu on the lock!’ cried Jack. ‘Like you did in prison.’