'That's better.' Rufus stared at his men. 'We don't know how long it's going to take to catch the enemy. That water in your canteen is all that you have. You try even a sip of this liquid shit we're wading through and you won't have a dry arse for a month. If you live that long. So, you only drink from your canteen, and only when I say so. Is that clear?'

The men nodded.

'Then pick up your shields and let's move.'

Cato regarded the centurion with approval. Rufus was clearly old school despite a relatively soft posting to Egypt where the legions had not had to participate in a major campaign in living memory. His tone, bearing and the scars on his arms and face marked him out as a professional soldier, much like Macro, Cato decided.

There was a swirl in the rushes close by and a splashing as something large lunged towards Cato. He turned and crouched as he ripped out his sword and raised his shield. A hideous dark shape, water glistening on its knotted hide, burst from between the reeds and a long tooth-lined jaw opened and snapped down on the shoulder of the dead man. Cato froze for an instant, and before he could react the beast lurched back, dragging the corpse with it. There was a last blur of movement, and a leg jerked lifelessly and then the monster and the body were gone. Only the disturbed water, swaying reeds and the rapidly fading sound of splashing remained.

Cato swallowed, and stared at Rufus wide-eyed. 'What the hell was that?' he muttered.

'Crocodile,' the centurion replied, warily watching the spot where the beast had disappeared, as if it might return at any moment.

'Crocodile?' Although Cato had been warned about them this was the first he had seen up close.

Rufus nodded. 'They live on the Nile, and here in the delta.'

'So I've heard.' Cato slowly straightened up. 'Not too thick on the ground, I trust?'

Rufus slapped his cheek. 'Not as thickly as the insects… But there are enough of them about to cause a problem. The natives tend to keep away from them.'

'No surprises there.'

'Even so, the crocodiles take the odd peasant, or their mules.'

'They don't hunt them?'

Rufus smiled thinly. 'Who would want to? Besides, they're sacred to the natives.'

'Sacred?'

Rufus looked surprised. 'You've been aboard the Sobek for two months and you haven't worked that out, sir?'

'What?' Cato responded irritably.

'Sobek is the name of their crocodile god, sir.'

Cato frowned, cross with himself not to have made the connection. 'Well, if any of them get that close to me again, I may be up for a little sacrilege.'

'I doubt you'd get the chance, sir. They might look cumbersome, but I assure you they can outrun a man on land and outswim him in the water. Best stay clear of them, sir. Them and the snakes.'

'Snakes? Venomous snakes, I take it.'

'Deadly. The cobras particularly, sir. Though they prefer drier ground.'

'That's a small comfort. We have to go.' Cato turned to the other men and saw that several of them were still staring nervously in the direction of the fading rustling and splashing. 'The column will advance!'

He turned, lifted his shield with a grunt and set off again, warily glancing from side to side as he waded through the reeds. The thought of encountering another crocodile unnerved him, but Cato knew that they must press on. Ajax must be caught, whatever the cost. Cato thrust the thought to the forefront of his mind. That was all that mattered. He must lead by example and he forced himself on, pressing forward through the broken reeds, no matter what lurked there.

The column trudged on through the swamp as the sun rose higher into the sky and caught the soldiers in its full glare. The air, trapped and still, grew hotter by the hour and Cato's mouth began to dry out and then a raging thirst burned in his throat. On his own he would have taken a drink from his canteen by now, but he was waiting for Rufus to give the order to his men first. It would not do to be seen to be weaker than the centurion in the eyes of the other men. So he endured the thirst for a while longer, and then began to wonder if Rufus was refusing to call a halt and allow the men to drink for precisely the same reason. Cato stole a glance back over his shoulder. Rufus was ten feet or so behind him, sweating freely, his lined face gleaming with perspiration, but his expression was fixed and revealed nothing of his thoughts.

At noon the reeds gave way to a small island covered in long grass and Cato took the chance to let the men rest. As they emerged from the water on to solid ground, Cato strode forward a few more paces and lowered his shield, leaning to rest his arms on the rim as he caught his breath. One by one the legionaries emerged from the reeds, staggered up and slumped down in the grass either side of the trail.

'Reckon the men could use some water, sir,' Rufus rasped as he wiped his brow with the back of his forearm. 'I know I could.'

'All right.' Cato nodded. 'Let 'em drink. But mind they take no more than a mouthful.'

'Yes, sir.'

As the men took their meagre refreshment, under the watchful eyes of Rufus, Cato lifted his canteen and allowed himself a small amount, which he swilled slowly around his mouth before swallowing. Then he put the canteen away and paced up to the highest point on the island to search for any sign of life to the south, the direction Ajax seemed to have veered towards during the morning. There was a small clump of date palms nearby, and a handful of fallen trunks amid a tangle of old brown fronds. Cato made his way across to them and stepped up on to one of the trunks. From his vantage point he could see an unbroken sprawl of reeds interspersed with dense clumps of trees and undergrowth stretching out in front of him. But no sign of any movement. The stillness depressed him. He had hoped to have marched quickly enough to have caught up with Ajax and his men. Cato was also worried. There had been no word from the section Rufus had sent forward to stay in contact with the enemy. They might be far ahead, or they could have lost their way. Cato turned round to look back on their tracks. Even though he calculated that they had come no more than five miles over the difficult ground, there was no sign of life. The horizon was clear and nothing moved amid the reeds they had passed through.

After another brief look ahead, Cato returned to the column and wearily picked up his shield. 'The rest is over, Centurion. Get the men back on their feet.'

A brief look of surprise flitted across Rufus's face before he nodded and faced his men, hands on hips. 'Up you get, ladies!'

There was a chorus of groans and muttered growls of complaint before Rufus cleared his throat and bellowed at them. 'Silence! I gave you a bloody order. Get up. It's time for you to earn your pay. This is what the Emperor's silver is for, and he pays you handsomely. So shut your mouths and pick up your kit, damn you!'

The men rose stiffly and made ready to continue the march. Rufus turned to Cato. 'At your command, sir.'

'Thank you. Forward then.'

Rufus raised his arm and swept it towards the broken trail. 'Column! Forwards!'

With Cato in the lead once more, they trudged through the tall grass to the far side of the island and back into the still, murky waters surrounding the beds of reeds. The afternoon was the hottest part of the day and the heat beat down on the extended line of soldiers and some dipped their felt helmet liners into the water before cramming them over their heads to provide some comfort from the baking temperature. Towards the middle of the afternoon they came across another body, between the twisting roots of a tree. As before, he bore wounds from the morning's fight and had been despatched by a sword thrust. Cato examined him briefly before moving on.