'How much further to the camp?' asked the Greek, looking back over his shoulder yet again.'Will we reach it before dark?'

The decurion in charge of the small mounted escort spat out an apple seed and swallowed the sharp-tasting pulp before replying.

'We'll make it. Don't you worry, sir. Five or six miles, I reckon. That's all.'

'Can't we go faster?'

The man was still looking over his shoulder and the decurion could no longer resist the temptation to glance back along the track. But there was nothing to see. The route was clear all the way to the saddle nestling between two densely wooded hills that shimmered in the heat. They were the only people on the road, and had been since leaving the fortified outpost at noon. Since then the decurion, the ten mounted men of the escort he commanded, and the Greek with his two bodyguards, had been following the road towards the massive forward camp of General Plautius. There, three legions and a dozen auxiliary units were concentrated in order to strike a final decisive blow against Caratacus and his army of Britons, drawn from the handful of tribes still openly at war with Rome.

Quite what business this Greek had with the general was a source of great curiosity for the decurion. At first light he had been ordered by the prefect of the Tungrian cavalry cohort to turn out the best men from his squadron and escort this Greek into the presence of the general. He did as he was told and asked no questions. But now, as he looked sidelong at the Greek, he was curious.

The man reeked of money and refinement, even though he wore a plain light cloak and a simple red tunic. His fingernails were carefully manicured, the decurion noted with distaste, and from the thinning dark hair and beard wafted the scent of an expensive citron pomade. There was no jewellery on his hands, but pale white bands showed that the Greek was accustomed to wearing a range of ostentatious rings. With a slight curl of his lip the decurion put the man down as one of those Greek freedmen who had wormed their way into the heart of the imperial bureaucracy. The fact that the man was now in Britain, and so obviously not trying to draw attention to himself, meant that he was on some detached duty of such sensitivity that the imperial courier system could not be trusted with the delivery of the message to the general.

The decurion subtly shifted his gaze to the two bodyguards riding immediately behind the Greek. They were equally plainly dressed and under their cloaks they carried short swords hanging from army-pattern baldrics. These were not the ex-gladiators that the most wealthy men of Rome preferred to employ as bodyguards. The swords and their bearing were a dead giveaway and the decurion recognised them for what they were: Praetorian Guardsmen, attempting – and failing – to go undercover. And they were the final proof that the Greek was here on imperial business.

The palace official looked back once again.

'Missing somebody?' asked the decurion.

The Greek glanced round, then suppressed his anxious expression and forced a small smile on to his lips. 'Yes. At least I hope so.'

'Anybody I should be warned about?'

The Greek stared at him for a moment and then smiled again. 'No.'

The decurion waited for the man to elaborate but the Greek cut him dead and faced forward. Taking another bite of his apple the decurion shrugged and let his gaze wander across the surrounding countryside. To the south the upper reaches of the river Tamesis looped through the undulating landscape. Ancient woodlands hugged the tops of hills, while around them were dotted the small settlements and farms of the Dobunnian tribe – one of the first to pay homage to Rome when the legions had landed over a year earlier.

This would be a nice place to settle down, the decurion mused. Once he had served his twenty-five years and was awarded citizenship and a small gratuity, he would buy a farm on the edge of a veterans' colony and end his days in peace. He might even wed that native woman he had picked up in Camulodunum. Raise a few kids and drink himself silly.

The warm comfort of this reverie was interrupted as the Greek suddenly reined in and stared back down the track, brown eyes narrowed beneath his plucked brows. With a mouthed curse the decurion raised his arm to halt his men and then turned to his nervous charge.

'What now?'

'There!' The Greek pointed.'Look there!'

The decurion wearily twisted on his saddle, the leather creaking under his riding breeches. For a moment he saw nothing; then as his gaze lifted to where the track disappeared over the hill he saw the dark silhouettes of horsemen flying from the shadows of the trees. Then they emerged into the sunlight, galloping straight towards the Greek and his escort.

'Who the hell are they?' the decurion muttered.

'I've no idea,' replied the Greek, 'but I think I know who sent them.'

The decurion glanced at him irritably. 'They're hostile?'

'Very.'

The decurion ran an experienced eye over their pursuers, now little more than a mile away: eight of them, their dark brown and black cloaks fluttering behind as they bent low over their mounts and urged them on. Eight against thirteen – not counting the Greek. Favourable odds, the decurion reflected.

'We've seen enough.' The Greek turned away from the distant horsemen and kicked his heels in. 'Let's go!'

'Forwards!' commanded the decurion, and the escort galloped after the Greek and his bodyguards.

The decurion was angry. There was no need to run like this. They had the advantage and could rest their mounts and wait for the pursuers to catch up, on blown horses. It would be over quickly enough. Then again, there was a vague chance that someone might get lucky and have a go at the Greek. The prefect's orders had been quite explicit: no harm must come to the Greek. His life must be protected at any cost. In that light, distasteful as it may be, the best thing to do was to stay out of harm's way, the decurion admitted. They had a mile's head start and would surely reach the general's camp long before the horsemen came within striking distance.

When he next looked over his shoulder the decurion was shocked to see how much closer the pursuers had come. They must be superbly mounted, he realised. His own horse, and those of his men, were as good as any in the cohort, but now they were wholly outclassed. And even then the pursuers would have to be fine riders to wring such performance out of them.

For the first time, the decurion was pricked by doubt. These were no mere brigands. Nor were they natives of this island, judging from their dark hair, swarthy complexions and flowing cloaks and tunics. Besides, Celtic tribesmen attacked Romans only when they heavily outnumbered them. Then again, the Greek seemed to know them. Even allowing for the timorous-ness of his race, the man's terror was palpable. Ahead of the decurion the Greek bounced up and down precariously on the back of his mount, while to each side his bodyguards rode their beasts with rather more style and confidence. The decurion's lips lifted in a wry grin around his gritted teeth. While the Greek might have acquitted himself well in the palace, he rode deplorably.

It wasn't long before the inevitable happened. With a sharp cry the Greek bounced too far to one side and despite a last desperate jerk of the reins his momentum hurled him from his saddle. Swearing, the decurion just managed to steer his beast to one side to avoid trampling the fallen man.

'Halt!'

With a chorus of curses and alarmed whinnying from the ponies, the escort drew up around the Greek, sprawled on his back.