This was supposed to be a secret mission. As far as he knew, only the Emperor himself and a handful of Claudius' most trusted officials were privy to the knowledge that the Emperor's right-hand man had been sent to Britain to meet with General Plautius. The last time he had met the general, a year ago, Narcissus had been part of the imperial retinue when Claudius had joined the army just long enough to witness the defeat of the native army outside Camulodunum, and then claim the victory as his own. The imperial retinue had numbered thousands and no luxury or security had been spared for the Emperor and Narcissus. This time discretion was paramount and Narcissus, travelling in secret without any of his cherished adornments, had asked the prefect of the Praetorian Guard to lend him the two best men of this elite unit. So he had set out from a quiet backstreet exit of the palace in the company of Marcellus and Rufus.

But somehow the news had leaked out. Almost as soon as he was out of sight of Rome Narcissus suspected that they were being watched and followed. The road behind them had never been quite deserted – always some solitary figure dimly visible far down the road behind them. Of course, such figures might have been quite innocent, and his suspicions groundless, but Narcissus was haunted by fear of his enemies. Haunted enough to take every precaution he could, and he had lasted longer than most men in the perilous world of the imperial household. A man who played for high stakes, as Narcissus did, had to have eyes in the back of his head and see everything that happened around him: every action, every deed, every quiet tilt of the head amongst aristocrats as they exchanged whispers at palace banquets.

It often reminded him of the god Janus, the two-faced guardian of Rome, who watched for danger in both directions. Being part of the imperial household required wearing two faces: the first an eager servant willing to please his political master and social superiors; the second a fixer of utter ruthlessness and determination. The expression of his true thoughts was only permitted when confronting men he had had condemned to execution, when there was great satisfaction to be had in releasing his scorn and contempt for them.

Now, it seemed, it might well be his turn for extermination. Much as he was terrified of death, Narcissus was consumed with the need to know who, amongst the legions of his bitter enemies, had planned this. There had already been two attempts, the first at an inn in Noricum, where a fight had started over a few spilled drinks and quickly escalated into a general brawl. Narcissus and his bodyguards had been watching from a cubicle when a knife had flown across the room straight at him. Marcellus saw it coming and shoved the Imperial Secretary's head down into his bowl of stew, the blade thudding into the timber post behind Narcissus an instant later.

On the second occasion a party of horsemen had appeared on the road behind them as they headed towards the port of Gesoriacum. They had taken no chances and galloped ahead of the horsemen, arriving in the port on blown horses that had been pushed to the limits of their endurance. The quay was packed with shipping; supplies destined for Plautius' legions were being loaded on vessels bound for Britain, while ships returning from the island were busy unloading prisoners of war destined for slave markets across the Empire. Narcissus took berths on the first ship to leave for Britain. As the freighter pulled away from the chaotically busy quay Marcellus had gently touched his arm and nodded to a group of eight men silently watching the ship depart. The same men, no doubt, who were pursuing them now.

Narcissus glanced back and was shocked to see how much they had closed the gap. By contrast the camp seemed as far away as ever.

'They're catching us up,' he cried out to his bodyguards.'Do something!'

Marcellus spared his Praetorian companion a quick glance and both men raised their eyes.

'What do you reckon?' Rufus called out. 'Save ourselves?'

'Why not? Damned if I'm going to die for some Greek.'

They hunkered down beside their horses' necks and spurred them on with wild shouts.

As they pulled ahead Narcissus cried out in panic, 'Don't leave me! Don't leave me!'

The Imperial Secretary kicked his heels in and his mount gradually caught the others up. As the acrid odour of horseflesh filled his nostrils and every jolt of the horse threatened to hurl him down on to the ground rushing past in a blur, Narcissus gritted his teeth in terror. He had never been so afraid in all his life, and vowed not to ride one of these animals ever again. From now he would travel in nothing faster, or less comfortable, than a litter. As he drew level with his bodyguards Marcellus tipped him a wink.

'That's more like it, sir… Not so far now!'

The three of them pounded on, wind roaring in their ears, but every time that Narcissus or one of the bodyguards glanced back the horsemen were nearer. As the track drew closer to the camp the horses of prey and pursuer alike began to flag and the riders felt their mounts' chests expand and contract like huge bellows as the animals struggled for breath. The breakneck gallop subsided into an exhausted canter as the men became more savage in their attempts to wring every last effort out of their horses.

When the track reached the next bit of high ground Narcissus saw that they were no more than two miles from the safety of the camp and numerous parties of men were training or foraging in the open ground before the ramparts. Surely the approaching riders must have been seen by now? The alarm must have been raised and a force sent out to investigate. But the three men gazed down on a serene and undisturbed scene as they spurred their tired mounts on. And all the time the gap between them and their pursuers closed.

'They must be fucking blind!' Rufus called out bitterly, wildly waving an arm. 'Over here, you dozy bastards! Look over here!'

The track dipped down again, towards a brook that meandered along the edge of a small wood of ancient oak trees. The placid surface of the water exploded as Narcissus and his bodyguards splashed through the ford and emerged glistening on the far side. The horsemen were no more than two hundred paces behind as their prey galloped along the track winding through the oak trees. The path was well worn and deep wagon ruts forced them to the side to spare their mounts the risk of broken legs. There was gorse in the undergrowth and Narcissus felt it tear at his breeches as they raced on, heads lowered to avoid being knocked by projecting branches. The distant thrashing of water revealed that their pursuers had reached the ford.

'Nearly there!' Marcellus shouted. 'Keep going!'

The route wound through the trees, sunlight dappling the ground where it broke through the green canopy above the riders. Then the way opened out ahead of them and in the distance lay the fortified gate of the camp. Narcissus felt a surge of joy at the sight and the realisation that they might be spared after all.

The horses, dripping with water and perspiration, galloped out into the sunshine.

'You there!' a voice barked out. 'Halt! Halt!'

Narcissus saw a party of men resting in the shade of the trees at the fringe of the wood. Around them lay piles of freshly cut wood, and pack mules grazed contentedly. Javelins were stacked within easy reach and the men's shields were standing on their curved bases, ready to be snatched up at a moment's notice.

Marcellus jerked his reins in savagely and his horse slewed towards the firewood detachment. He drew a deep breath and shouted, 'To arms! To arms!'

The men reacted at once and jumped up and ran for their weapons as the three horsemen galloped towards them. The optio in charge of the detachment strode forwards, his sword raised warily.