The three men watched the galleon glide past, eerie and ominous as a monster of the deep. A little further along the shore – just as the constable had predicted – the boat’s keel ploughed into the soft silt of the estuary’s bank and the ship shuddered to a halt. The three men exchanged an uneasy look, then took off down the beach. Their feet squelching in the sodden sand, they approached the galleon. The vessel lay still and bloated as a beached whale.

‘Ahoy there!’ cried the customs officer, craning his neck towards the upper deck.

But there was no reply, only the creak of timbers, the loose flap of a sail and the lapping of water against the hull.

The watchman swallowed uneasily. ‘Shouldn’t we call for the militia?’

The customs officer sneered. ‘And incur the wrath of Sir Francis for waking him at this ungodly hour? No, we investigate further before disturbing the Lord Lieutenant from his bed.’ He gestured towards a loose rigging rope dangling over the side of the ship. ‘Go and look, constable.’

Hooking his cudgel to his belt, the constable waded through the water, then hauled himself up the barnacled planking and over the gunwale. All remained ominously silent. The watchman pulled the collar of his cloak even tighter, the chill in his bones not from the sea mist but from the galleon’s sinister arrival. As they waited for the constable’s return, the customs officer’s feet began to sink into the silt.

‘What’s keeping him?’ he muttered, tugging a leather boot free and irritably kicking off the sludge.

Another minute or so passed. Then the constable’s bearded face appeared. ‘All clear,’ he called, and dropped down a rope ladder for them.

Splashing through the frigid sea, they caught hold of the ladder and clambered aboard. The upper deck was deserted. No lanterns were lit. Not a soul in sight.

The customs officer glanced sidelong at the constable. ‘Where’s her crew, then?’

The constable shrugged. ‘Below decks maybe.’

Cautiously the men approached the main hatch. The customs officer silently beckoned to the constable to open it. With a squeal of hinges, the hatch was heaved back. A set of wooden steps led down into the ship’s black belly.

‘Light,’ ordered the customs officer.

The watchman lit a lantern and passed it to him. The gloom fled the flames, and the customs officer gasped as the lower deck revealed itself. A sailor lay slumped against a wall, his head bent forward as if in sleep. But it was the sleep of the dead. A large black rat that had been gnawing on the man’s fingers scuttled away as soon as the lamplight hit it.

The watchman’s sunken cheeks became even more hollow. ‘You think she’s a plague ship?’