The heaving tumult around the ship was frozen for an instant by sheet lightning. All around, the foaming sweep of the sea stilled as the stark shadows of the sailors and the rigging scored the brilliantly lit deck of the trireme. Then the light was ripped away and darkness gripped the vessel once more. Black clouds hung low in the sky and billowed across the grey waves rolling down from the north. Nightfall was not yet upon them, yet it seemed to the terrified crew and passengers that the sun must have long since quit the world. Only the faintest smudge of lighter grey away to the west indicated its passage. The convoy was hopelessly scattered, and the prefect commanding the newly commissioned squadron of triremes swore angrily. With one hand firmly gripping a stay, the prefect used his spare hand to shield his eyes from the icy spray as he scanned the foaming wave tops around them.

Only two ships of his squadron remained in sight, dark silhouettes heaving into view as his flagship was raised on the crest of a great wave. The two ships were far off to the east, and beyond them would be the rest of the convoy, spread across the wild sea. They might still make the entrance of the channel that led inland to Rutupiae. But for the flagship there was no hope of reaching the great supply base that equipped and fed the Roman army. Further inland the legions were safely nestled in their winter quarters at Camulodunum, in readiness for the renewal of the campaign to conquer Britain. Despite the best efforts of the men at the oars, the vessel was being swept away from Rutupiae.

Looking across the waves to the dark line of the British coast, the prefect bitterly acknowledged that the storm had bested him, and passed the order for oars to be shipped. As he considered his options, the crew hurriedly raised a small triangular sail from the bows to help steady the vessel. Since the invasion had been launched the previous summer, the prefect had crossed this stretch of sea scores of times, but not in such dreadful conditions. Indeed, he had never before seen the weather turn so rapidly. That morning, which seemed so very long ago now, the sky had been clear and a brisk southerly promised a quick crossing from Gesoriacum. Normally no ships would put to sea in winter, but the army of General Plautius was short of supplies. The scorched-earth tactics of the British commander, Caratacus, meant that the legions depended on a steady supply of grain from the continent to get them through the winter without depleting the stockpiles necessary for continuing the campaign in the spring. So the convoys had continued to cross the channel whenever the weather permitted. This morning the prefect had been fooled by perfidious nature into ordering his laden vessels to set out for Rutupiae, never dreaming that they would be caught in this tempest.