Grumio was an acrobat. He had landed better than Philocrates and was on his feet straight away. He turned to follow the mule and escape on foot – just as Thalia had the far gate swung closed against him. Designed for keeping in wild beasts, it was far too tall to climb. He spun back – and met me. Still dressed as the ghost, I tried to fill enough space to block his exit the other way. The gateway behind me gaped open at least twelve feet wide, but members of the company were pressing into it, eager to see the action. They would not let him through.

It was him and me now.

Or rather, it was more than that, for two other figures had emerged. For that last scene in the arena it would be him and me – plus Musa and the sacrificial kid.

Ensemble playing of the finest quality.

Chapter LXXIII

I wrenched off the mask. Its flowing grey locks, made from rough horsehair, caught in my fingers. Shaking it free with some violence, I hurled it away.

Blinking in the torchlight, I saw Helena standing up in the tribunal, talking urgently to the commander. Davos was leaping down the steps towards the front, taking the treads three at a time. The Palmyra garrison must have some troops who were not quite the dregs; soon there was a flurry of controlled activity at one end of a row.

A long way behind me, Musa stood with the kid in his arms. He was crazy; a Nabataean; from another world. I could not understand the idiot. 'Back off. Get help!' He ignored my shout.

I gathered the ludicrous folds of the costume and stuffed them in my belt. The crowd suddenly fell so completely silent that I could now hear the flames on the bitumen torches that stood around to light the stage. The soldiers had no idea what was happening, but they knew it was not in the programme. I had a bad feeling that The Spook who Spoke was turning into something they would talk about for years.

Grumio and I were standing about fourteen feet apart. Scattered around were various props, mostly items left as hiding places for the ghost: the craggy rock; the beehive oven; a wicker laundry trunk; a couch; a huge ceramic pot.

Grumio was enjoying it. He knew I would have to take him. His eyes were flashing. His cheeks were flushed hectically. He looked drugged with excitement. I should have known all along he was one of those tense, arrogant killers who destroy life coldly and never recant.

'This is the killer from the High Place,' stated Musa, publicly inditing him. The bastard coolly started whistling.

'Give up.' My voice was quiet, addressing Grumio. 'We have evidence and witnesses. I know you killed the playwright because he would not return your missing scroll – and I know you strangled Ione.'

' " Now she's dead, which takes away some of the problem…"' He was quoting The Girl from Andros. The sheer flippancy enraged me. 'Don't come any closer, Falco.'

He was mad, in the sense that he lacked humanity. In every other sense he was as sane as me, and probably more intelligent. He was fit, athletic, trained to do sleight of hand, keen-sighted. I did not want to have to fight him – but he wanted to fight me.

A dagger was in his hand now. My own knife came from my boot into my grip like a friend. No time to relax, however. He was a professional juggler; if I came too close I was likely to find myself weaponless. I was unarmoured. He, casting aside the cloak from his costume, was at least protected by the leather apron of a stage slave.

He crouched, feinting. I stayed upright, refusing to be drawn. He snarled. I ignored that too. I started circling, weight secretly on the balls of my feet. He prowled too. As we spiralled gently, the distance between us reduced. On the long-benched galleries, the soldiers started a low drumming of their heels. They would sustain the dreadful racket until one of us was done for.

My body felt stiff. I realised just how long it was since I had exercised in a gymnasium. Then he came for me.

The fight was fierce. He had nothing to lose. Hate was his only incentive; death now or later the only possible prize.

One thing was pretty obvious: the garrison enjoyed gladiators. This was better than mere comedy. They knew the knives were real. If someone got stabbed, the blood would not be cochineal.

Any thought that the officer in charge would send men in to help me faded early. There was a group in armour at each gate now, but they were just standing there for a better view. If anyone from the theatre company tried to rush on and assist, the soldiery would hold them back and call it keeping the peace. Their commander would know his best hope of maintaining order was to allow the contest, then either praise me or arrest Grumio, whoever survived. I was not taking bets; nor was the officer, I guessed. Besides, I was an imperial agent. He would expect a certain standard of competence, and if I failed to find it, he probably would not care.

Things began stylishly. Cut and slash. Parry and thrust. Balletic moves. Soon choreographed into the usual panic, heat and mess.

He tricked me. Dismayed, I fled; rolled; threw myself at his feet as he ran at me. He leapfrogged over me and dodged behind the laundry basket. The soldiery roared. They were on his side.

He was safe. I had to be more cautious.

I grabbed the spook's mask and flung it at him. Ever the juggler, he caught the thing and sliced it at my throat. I was no longer there. He spun; glimpsed me, so he thought; felt my knife rip the back of his tunic; but managed to slide out of it.

I pursued. He stopped me with a tornado of whipping strokes. Some bastard in the audience cheered.

I kept my head. I had been the unfavoured man before. Plenty of times. Let him think he had the crowd. Let him believe he had the fight: Let him jab me in the shoulder as the ghost's robes untwined around my feet and tripped me up.

I got out of that. With an ungainly clamber I straddled the wicker basket, flopped over it and just found time to thrust the folds of dragging material back in my belt. I stopped thinking pretty thoughts. Stuff strategy. Best just to react.

Stuff reacting. I wanted to finish it.

Grumio suspected the trip had thrown me. He was coming for me. I grabbed his knife arm. The dagger flipped across to his other hand: an old trick, and one I recognised. He stabbed up at my ribs, only to gasp as my knee hit his left wrist and cheated him of his intended blow. Now I was the one who was laughing while he looked stupid and yelled.

Taking advantage of his lapse in concentration, I fell on him. I had trapped him on top of the laundry basket. It lurched wildly as we struggled. I slammed Grumio's arm against the lid. I pinned him to the basketwork. I managed to press my own arm down on to his throat.

He looked thinner, but was as strong as me. I could find no better purchase. I knew that any minute he would fight back and it would be my turn to be hammered. Desperate, I rammed his body against the prop, so the whole basket skidded forwards. We both fell.

Grumio scrambled up. I was coming after him. He hurled himself across the basket as I had done earlier, then turned back. He withdrew the wedge from the clasp and pulled up the lid in my face.

The lid dropped open, on my side. Grumio had dropped his dagger but made no attempt to retrieve it. The thunder of boots from the soldiers stilled. Grumio stood transfixed. We both stared at the basket. There was an enormous snake looking out at Grumio.

The thud of the lid had mobilised the reptile. Even I could tell it was disturbed by the blaze of the torches, the strange setting, the violent shaking it had just experienced. Slithering restlessly, it swarmed out of the chest.

A gasp ran around the amphitheatre. I was gasping myself. Yard after yard of diamond-patterned scales ran from the basket to the ground. 'Keep away!' Grumio yelled at it. No use. Snakes are nearly deaf.