Meanwhile, the last deserter made for the exit from which he'd been expelled, and began ripping at the bricks with his bare hands. 'Help me,' he shouted, reaching his bloodied fingers through a tiny gap in the wall. 'For pity's sake!' From only an arm's length away, Romulus and Petronius watched in total revulsion as a wolf jumped on to the man's back. Placing its large paws on his shoulders, it sank its teeth into the back of his head. Stumbling backwards with his arms flailing, the soldier was a perfect target for another wolf. It darted in and grabbed hold of his groin, eliciting a cry of agony that made Romulus wince and turn aside.

He could not block out the terrible sounds of distress as the deserter was torn apart half a dozen paces away. Or the delirious shouts from the people sitting overhead. While Romulus had no sympathy for men who would run and leave their comrades in the midst of a battle, he didn't think that they deserved to die like sheep, or deer. Crucifixion was brutal beyond belief, but this was worse. To the rabid citizens above, however, this was justice being done.

It was a long while before all the shrieking stopped, but the men's deaths did not bring silence to the arena. Instead the screams were replaced by the growls of wolves arguing over their prey, and the noise of bones being cracked by powerful jaws. The spectators began to lose interest and soon, the predators were forced out of the arena by dozens of slaves. While some banged drums and cymbals to cause confusion, others carried shields and flat pieces of wood. Walking close together in a long line, they herded the wolves back through the open grilles and into their cages.

During this interlude, Memor reappeared in the corridor. With a cruel wink at Romulus, he picked the second trio of soldiers and sent them out to face two bears and a pair of wild bulls. Still giving the friends no clue as to what they'd face, he disappeared again. Romulus' stomach clenched into a tight knot, and he sat down. He was damned if he'd watch another spectacle like the previous one. Besides, his fear was threatening to overcome him. Although death had been omnipresent in his life since Gemellus had sold him into the Ludus Magnus, some tiny chance of survival had always appeared. He'd beaten an older, more experienced gladiator; he'd survived the slaughter at Carrhae to be taken prisoner; he'd escaped the almost-certain annihilation of the Forgotten Legion by a vast Indian army. Now, with his ears ringing with the dying howls of his fellow captives, his life seemed to have come to a complete dead end.

He glanced at Petronius, who was sitting beside him. The veteran's eyes were closed, and he was muttering a prayer to Jupiter. He's more composed than I am, thought Romulus with surprise, and the poor bastard shouldn't even be here. He could have walked away and left me to it. A true friend, he didn't. Shame filled Romulus. How could Petronius face death like a man when he was acting like a scared child? His comrade deserved more respect.

'Time's up,' Memor's voice broke in.

Romulus looked up. Hands on hips, the smirking lanista was standing a few paces away. Only the metal of the cage separated them. 'What I'd give for a chance to rip your throat out,' he said from between gritted teeth.

Memor grinned. 'Sorry,' he said. 'If that happened, my guards would kill you. Then the good people of Rome wouldn't get to see the final spectacle of the morning. Can't have that, can we?'

Romulus got to his feet.

Deep in his own world, Petronius stayed where he was.

Dusting his hands off, Romulus moved right up to the bars. All he was going to show from this moment on was steely determination. 'What have you got in store for us, you old shitbag?' he demanded fiercely.

Surprised, Memor took a step back. He was quick to recover his poise, though. 'An Ethiopian bull,' he replied. 'Some call it a rhinoceros.'

Studiously ignoring the lanista, Petronius stood up and watched the guards opening the exit. The only sign of his inner tension was his jaw clenching and unclenching. The wilder rumours in the ludus had included an armoured beast with the colloquial name of 'Ethiopian bull'. They had been terrifying.

Trying to protect his friend, Romulus had denied all knowledge of it. A pointless gesture, he now saw. He gripped the bars tightly, remembering the capture of a rhino he'd witnessed when working for Hiero. It had taken nearly a score of slaves with ropes and nets to subdue the giant two-horned creature enough to get it in a cage. More than one slave had died in the process. Plenty of others had been hurt in the weeks and months that followed. Irritable and aggressive, the rhino had been Hiero's prize capture. It could even be the same beast, Romulus reflected. How ironic. He closed his eyes and sent up a prayer to Mithras. Grant us a swift death.

Memor chuckled. 'You should never have run away,' he said, almost regretfully. 'Might have even won a rudis by this stage. Made me a fortune in the process. Now look at you.'

There was a clunking sound as the heavy planks of the exit were lifted and then placed on the ground. Blinding sunlight poured into the cage, making it difficult to see out into the arena. As usual in breaks between bouts, the audience was largely silent. All that could be heard were the voices of mobile food vendors hawking their wares of sausages, bread and watered-down wine, and bookmakers offering odds on the gladiator fights which would take place later in the day.

'Burn in Hades, Memor,' Romulus spat. Without waiting for a response, he trotted out on to the sand. It was the only gesture of defiance he could make. That, and dying like a man.

Casting dreadful aspersions on the lanista's parentage, Petronius followed.

Memor did not reply. Instead the planks were replaced, leaving the friends stranded in the arena. People noticed the activity on the sand, and turned from their conversations. 'Deserter scum,' shouted a portly figure in a ragged tunic. 'Cowards,' cried another. Their accusations were infectious and soon insults were pouring down on the pair.

The fact that desertion was not their crime was irrelevant, thought Romulus. Place anyone in this circle of death and the citizens would assume that they were guilty. And he was, technically. Although he'd been press-ganged into the Twenty-Eighth, Romulus had joined Crassus' army as a slave. Yet, even facing this most brutal of ends, he was glad that he had. What momentous things he had seen in only eight years – and what friends he'd made in Brennus, Tarquinius and Petronius. His only regret now was not being able to speak with Fabiola for just a few moments. That, and being reconciled with the haruspex.

'This Ethiopian bull,' said Petronius. 'Does it really have a horn as long as a man's arm?'

'Yes.' Romulus could still picture the slave he'd seen being gored by Hiero's rhinoceros. His had been a lingering death. 'At least that length.'

'It's twice as big as any bull?'

'Or more,' Romulus admitted. 'Aggressive too. One small help is that it's half-blind.'

'So what? We can't hide anywhere.' Fear surfaced on Petronius' face at last, but he did not panic. 'What do you think we should do?' he asked, his deferential tone giving Romulus the leader's role.

Romulus scanned the perimeter of the enclosure. There were no spikes to prevent animals jumping out, but at regular intervals stood spearmen and archers. Any attempt to escape would win them the same fate as the deserter a short time previously. He looked up at the sky, hoping against hope to be given a sign. A clue. Anything at all. He wasn't. It was just another glorious autumn morning. 'Don't know,' he said heavily. 'I can't think.'

Petronius barked a derisory laugh. 'Me neither,' he said. 'Still, it was good knowing you.'

'Aye, comrade,' answered Romulus. 'It was.'