Cato smiled and then looked back towards the shore. The slave compound was an ugly blot on the side of the hill overlooking the bay. All was still, save for a single flickering torch above the gate, and the dim form of a sentry standing close by as he kept watch over the slaves inside. This was the industrial side of slavery, which was largely invisible to most Romans, especially those well born, like Senator Sempronius and his daughter. The perfumed, uniformed slaves of a rich household were a far cry from the ragged masses who laboured in work camps, always tired and hungry and carefully watched for any sign of rebellion, which would be punished with brutal swiftness and severity.

It was a harsh regime, but the empire, and indeed every civilised nation that Cato knew of, depended on slavery to create wealth and feed its urban multitudes. For Cato it was a harsh reminder of the terrible differences in destiny that fate dealt out to people. The worst excesses of slavery were a blight on the world, he reflected, even if the institution was, for the present, a necessity.

He suddenly felt a faint tremor in the deck beneath his boots and glanced down.

'What the fuck?' Macro growled. 'Do you feel that?'

Julia grabbed Cato's arm. 'What is it? What's happening?'

There were cries of surprise and alarm across the deck as the crew and other passengers of the Horus glanced down at the deck.

'We've run aground,' said Sempronius, as he gripped the side rail.

The captain shook his head. 'Impossible! We're too far off the shore. I know these waters. There's no shallows for fifty miles. I swear it. In any case . . . Look there! At the sea.'

The captain thrust out his arm and the others followed the direction and saw that the surface of the water was shimmering faintly. For a brief time that seemed far longer than it was, the dull shudder of the deck and the quivering surface of the sea continued. Several of those on board fell to their knees and began to pray fervently to the gods. Cato held Julia in his arms and stared over her head at his friend. Macro gritted his teeth and glared back, hands clenched into fists at his sides. For the first time, Cato thought he saw a glimmer of fear in the other man's eyes, even as he wondered what was happening.

'A sea monster,' Macro said quietly.

'Sea monster?'

'Has to be. Oh, shit, why the hell did I agree to travel by sea?'