I take the old road that curves behind the west wall before petering out into a track that leads nowhere but to the sand-filled ruins. Are the children still allowed to play there, I wonder, or do their parents keep them at home with stories of barbarians lurking in the hollows? I glance up at the wall; but my friend in the tower seems to have gone to sleep.

All the excavation we did last year has been undone by driftsand. Only corner-posts stand out here and there in the desolation where, one must believe, people once lived. I scour a hollow for myself and sit down to rest. I doubt that anyone would come looking for me here. I could lean against this ancient post with its faded carvings of dolphins and waves and be blistered by the sun and dried by the wind and eventually frozen by the frost, and not be found until in some distant era of peace the children of the oasis come back to their playground and find the skeleton, uncovered by the wind, of an archaic desert-dweller clad in unidentifiable rags.

I wake up chilled. The sun rests huge and red upon the western horizon. The wind is rising: already flying sand has banked up against my side. I am conscious above all of thirst. The plan I have toyed with, of spending the night here among the ghosts, shivering with cold, waiting for the familiar walls and treetops to materialize again out of the dark, is insupportable. There is nothing for me outside the walls but to starve. Scuttling from hole to hole like a mouse I forfeit even the appearance of innocence. Why should I do my enemies' work for them? If they want to spill my blood, let them at least bear the guilt of it. The gloomy fear of the past day has lost its force. Perhaps this escapade has not been futile if I can recover, however dimly, a spirit of outrage.

I rattle the gate of the barracks yard. "Don't you know who is here? I've had my holiday, now let me back in!"

Someone comes running up: in the dim light we peer at each other through the bars: it is the man assigned as my warder. "Be quiet!" he whispers through his teeth, and tugs at the bolts. Behind him voices murmur, people gather.

Gripping my arm he takes me at a trot across the yard. "Who is it?" someone calls. It is on the tip of my tongue to reply, to take the key out and wave it, when it strikes me that this act might be imprudent. So I wait at my old door till my warder unlocks it, pushes me inside, and closes it on the two of us. His voice comes to me out of the darkness tight with anger: "Listen: you talk to anyone about getting out and I'll make your life a misery! You understand? I'll make you pay! You say nothing! If anyone asks you about this evening, say I took you out for a walk, for exercise, nothing more. Do you understand me?"

I unpick his fingers from my arm and slide away from him. "You see how easy it would be for me to run away and seek shelter with the barbarians," I murmur. "Why do you think I came back? You are only a common soldier, you can only obey orders. Still: think about it." He clutches my wrist, and again I loosen his fingers. "Think about why I came back and what it would have meant if I had not. You can't expect sympathy from the men in blue, I'm sure you know that. Think what might happen if I got out again." Now I grip his hand. "But don't fret, I won't talk: make up any story you like and I will support you. I know what it is like to be frightened." There is a long suspicious silence, "Do you know what I want most of all?" I say. "I want something to eat and something to drink. I am starved, I have had nothing all day." So all is as it was before. This absurd incarceration continues. I lie on my back watching the block of light above me growing stronger and then weaker day after day. I listen to the remote sounds of the bricklayer's trowel, the carpenter's hammer coming through the wall. I eat and drink and, like everyone else, I wait.

First there is the sound of muskets far away, as diminutive as popguns. Then from nearer by, from the ramparts themselves, come volleys of answering shots. There is a stampede of footsteps across the barracks yard. "The barbarians!" someone shouts; but I think he is wrong. Above all the clamour the great bell begins to peal.

Kneeling with an ear to the crack of the door I try to make out what is going on.

The noise from the square mounts from a hubbub to a steady roar in which no single voice can be distinguished. The whole town must be pouring out in welcome, thousands of ecstatic souls. Volleys of musket-shots keep cracking. Then the tenor of the roar changes, rises in pitch and excitement. Faintly above it come the brassy tones of bugles.

The temptation is too great. What have I to lose? I unlock the door. In glare so blinding that I must squint and shade my eyes, I cross the yard, pass through the gate, and join the rear of the crowd. The volleys and the roar of applause continue. The old woman in black beside me takes my arm to steady herself and stands on her toes. "Can you see?" she says. "Yes, I can see men on horseback," I reply; but she is not listening.

I can see a long file of horsemen who, amid flying banners, pass through the gateway and make their way to the centre of the square where they dismount. There is a cloud of dust over the whole square, but I see that they are smiling and laughing: one of them rides with his hands raised high in triumph, another waves a garland of flowers. They progress slowly, for the crowd presses around them, trying to touch them, throwing flowers, clapping their hands above their heads in joy, spinning round and round in private ecstasies. Children dive past me, scrambling through the legs of the grownups to be nearer to their heroes. Fusillade after fusillade comes from the ramparts, which are lined with cheering people.

One part of the cavalcade does not dismount. Headed by a stern-faced young corporal bearing the green and gold banner of the battalion, it passes through the press of bodies to the far end of the square and then begins a circuit of the perimeter, the crowd surging slowly in its wake. The word runs like fire from neighbour to neighbour: "Barbarians!"

The standard-bearer's horse is led by a man who brandishes a heavy stick to clear his way. Behind him comes another trooper trailing a rope; and at the end of the rope, tied neck to neck, comes a file of men, barbarians, stark naked, holding their hands up to their faces in an odd way as though one and all are suffering from toothache. For a moment I am puzzled by the posture, by the tiptoeing eagerness with which they follow their leader, till I catch a glint of metal and at once comprehend. A simple loop of wire runs through the flesh of each man's hands and through holes pierced in his cheeks. "It makes them meek as lambs," I remember being told by a soldier who had once seen the trick: "they think of nothing but how to keep very still." My heart grows sick. I know now that I should not have left my cell.

I have to turn my back smartly to avoid being seen by the two who, with their mounted escort, bring up the rear of the procession: the bareheaded young captain whose first triumph this is, and at his shoulder, leaner and darker after his months of campaigning, Colonel of Police Joll.

The circuit is made, everyone has a chance to see the twelve miserable captives, to prove to his children that the barbarians are real. Now the crowd, myself reluctantly in its wake, flows towards the great gate, where a half-moon of soldiers blocks its way until, compressed at front and rear, it cannot budge.

"What is going on?" I ask my neighbour.

"I don't know," he says, "but help me to lift him." I help him to lift the child he carries on his arm on to his shoulders. "Can you see?" he asks the child.