It is only hindsight that makes the first part of that journey appear relatively easy. At the time, as I stumbled after the lieutenant's striding figure, it certainly did not feel that way. My feet quickly began to smart from the rubble-strewn ground, and I found terribly awkward the contortions required to negotiate the holes in each wall.

Of the latter, there seemed an unending number, all of them more or less similar to the one in the cellar command base. Some were smaller, some large enough for two men to squeeze through at the same time; but they had all been gouged out with rough edges, and required a little jump to climb through. Before long I found myself close to exhaustion; no sooner had I clambered through one such hole than I would spot the lieutenant ahead of me, smartly easing his way through the next wall.

Not all the walls were still standing; sometimes we would pick our way through the debris of what must have been three or four houses before encountering another wall. The roofs were almost all smashed, often absent altogether, so that we had plenty of daylight from the sky – though here and there, heavy shadows made it easy to lose one's step. More than once, until I grew more accustomed to the terrain, my foot slipped painfully between two jagged slabs or sank ankle-deep into fragmented rubble.

It was all too easy in such circumstances to forget we were passing through what only several weeks before had been the homes of hundreds of people. In fact, I often had the impression we were moving through not a slum district, but some vast, ruined mansion with endless rooms. Even so, every now and then it would occur to me that in among the wreckage beneath our feet lay cherished heirlooms, children's toys, simple but much-loved items of family life, and I would find myself suddenly overcome with renewed anger towards those who had allowed such a fate to befall so many innocent people. I thought again of those pompous men of the International Settlement, of all the prevarications they must have employed to evade their responsibilities down so many years, and at such moments I felt my fury mount with so much intensity I was on the verge of calling out to the lieutenant to halt, just so I could give vent to it.

The lieutenant did, though, pause at one point of his own accord, and as I caught up with him, said:

‘Mr Banks, please take a good look at this.’ He was indicating a little over to our left, towards a large boiler-like construction which, though covered in masonry dust, had remained more or less intact. ‘This is the West Furnace. If you look up there, you will see the nearer of the two tall chimneys we saw earlier from the roof. The East Furnace is similar in appearance to this, and it will be our next clear landmark. When we reach it, we shall know we are very close to the house.’

I studied the furnace carefully. A chimney of some girth emerged from above its shoulders, and when I took a few steps closer and looked up, I could see the huge chimney going off way up into the sky. I was still staring up at it when I heard my companion say:

‘Please, Mr Banks. We must continue. It is important we complete our task before the sun sets.’

It was several minutes after the West Furnace that the lieutenant's manner became noticeably more cautious. His tread became deliberate, and at each hole, he would first peer through, his rifle poised, listening intently, before climbing up. I also began to spot more and more stacks of sandbags, or coils of barbed wire, left within reach of the holes. When I first heard the machine-gun, I abruptly froze, believing we were under fire. But then I saw the lieutenant before me still walking, and with a deep breath, went on after him.

Eventually I came through a hole to find myself in a much larger space. In fact, in my exhausted condition, I thought I had entered the bombed remains of one of those grand ballrooms I had been taken to in the Settlement. I then realised we were standing in an area once occupied by several rooms; the partition walls had almost entirely vanished, so that the next good wall was all of twenty-five yards away. There I could see seven or eight soldiers lined up, their faces to the brick. I at first took them for prisoners, but then saw how each man was standing before a small hole through which he had inserted the barrel of his rifle. The lieutenant had already crossed the rubble and was talking to a man crouched behind a machine-gun mounted on a tripod. This machine-gun arrangement was positioned before the largest hole – the one through which we would have to climb to continue our journey. Coming closer, moreover, I saw the perimeters of the hole had been decked with barbed wire, allowing only enough space for the gun barrel to manoeuvre.

I supposed at first the lieutenant was asking the man to remove this obstacle out of our way, but then I saw how tense all those present had become. The man behind the machine-gun, all the time the lieutenant spoke to him, never took his gaze from the hole before him. The other soldiers too, all along the wall, remained still and poised, their attention utterly focused on whatever was on the other side.

Once the alarming implications of this scene had sunk in, I felt inclined to climb back through the previous hole. But then I saw the lieutenant returning towards me and remained where I was.

‘We have some trouble,’ he said. ‘A few hours ago the Japanese managed to push forward a little way. We have now beaten them back again and the line has been re-established where it was this morning. However, it would seem several Japanese soldiers did not retreat with the others, and are now caught behind our line. They are completely cut off and thus very dangerous. My men believe they are at this moment on the other side of that wall.’

‘Lieutenant, you're not suggesting, are you, that we delay while this matter sorts itself out?’

‘I am afraid we will have to wait, certainly.’

‘But for how long?’

‘It is hard to predict. These soldiers are trapped, and they will be either captured or killed in the end. But meanwhile they have weapons and are very dangerous.’

‘You mean we could wait for hours? Days even?’

‘That is possible. It would be very dangerous at this point for the two of us to continue.’

‘Lieutenant, I'm surprised at you. I was under the impression that you, an educated man, were fully aware of the urgency of our present undertaking. Surely there's some other route we could take to by-pass these soldiers.’

‘There are other routes. But it remains the case that however we proceed, we will be in considerable danger. Unfortunately, sir, I see no alternative but to wait. It is possible the situation will be resolved before long. Excuse me.’

One of the soldiers by the wall had been signalling urgently, and now the lieutenant began to go across the rubble towards him. But just then the machine-gunner let loose a deafening burst of fire, and when he ceased there was an extended scream coming from beyond the wall. The scream began full-throated, then tapered off into a strange high-pitched whimper. It was an eerie sound and I became quite transfixed listening to it. It was only when the lieutenant came rushing back and pulled me down behind some fallen masonry that I realised there were bullets hitting the wall behind me. The men at the next wall were now firing too, and then the machine-gunner let off another burst. The authority of his weapon seemed to silence all the others, and thereafter, for what felt like an inordinate time, the only sound to be heard came from the wounded man beyond the wall. His high-pitched whimpers continued for several moments, then he began to shout something in Japanese over and over; every now and again the voice would rise to a frantic shriek, then die away again to a whimper. This disembodied voice echoed unnervingly around the ruins, but the Chinese soldiers in front of me remained utterly still, their concentration not wavering from what they could see through the wall. Suddenly the machine-gunner turned and vomited on the ground beside him, before immediately turning back to the wire-decked hole in front. From the way he did this, it was not easy to tell if his sickness had to do with nerves, the sounds of the dying man, or simply some stomach complaint.

Then eventually, though their postures hardly changed, the soldiers all perceptibly relaxed. I heard the lieutenant say beside me:

‘So you see now, Mr Banks, that it is no easy matter to proceed from here.’

We had been crouching down on our knees, and I noticed my light flannel suit was now almost entirely covered in dust and grime. I took a few seconds to collect my thoughts before saying:

‘I appreciate the risks. But we must nevertheless continue. Particularly with all this fighting going on, my parents shouldn't be left in that house a moment longer than necessary. May I suggest we take these men here with us? Then if these Japanese soldiers set upon us, we'd be much the stronger.’

‘As the commanding officer here, I cannot possibly sanction such an idea, Mr Banks. If these men leave their position, the headquarters would become entirely vulnerable. Besides, I will be putting the men's lives at needless risk.’

I gave a sigh of exasperation. ‘I must say, Lieutenant, it was pretty sloppy work on the part of your men to have allowed these Japanese in behind your line. If all your people had been doing their jobs properly, I'm sure such a thing would never have arisen.’

‘My men have fought with commendable bravery, Mr Banks. It is hardly their fault that your mission is, for the time being, inconvenienced.’

‘What do you mean by that, Lieutenant? What are you implying?’

‘Please calm yourself, Mr Banks. I am merely pointing out it is not the fault of my men if …’

‘Then whose fault is it, sir? I realise what you're implying! Oh yes! I know you've been thinking it for some time now. I was wondering when you'd finally come out with it.’

‘Sir, I have no idea what …’

‘I know full well what you've been thinking all this time, Lieutenant! I could see it in your eyes. You believe this is all my fault, all this, all of it, all this terrible suffering, this destruction here, I could see it in your face when we were walking through it all just now. But that's because you know nothing, practically nothing, sir, concerning this matter. You may well know a thing or two about fighting, but let me tell you it's quite another thing to solve a complicated case of this kind. You obviously haven't the slightest idea what's involved. Such things take time, sir! A case like this one, it requires great delicacy. I suppose you imagine you can just rush at it with bayonets and rifles, do you? It's taken time, I accept that, but that's in the very nature of a case like this. But I don't know why I bother to say all this. What would you understand about it, a simple soldier?’

‘Mr Banks, there is no need for us to quarrel. I have only the most sincere good wishes for your success. I am simply telling you what is possible …’

‘I'm getting less and less interested in your idea of what is and isn't possible, Lieutenant. If I may say so, you're hardly a good advertisement for the Chinese Army. Do I take it you're now going back on your word? That you're unwilling to accompany me beyond this point? I take it that's so. I'm to be left to carry out this difficult task by myself. Very well, I shall do so! I shall raid the house single-handed!’

‘I think, sir, you should calm yourself before saying anything more …’

‘And one other thing, sir! You can safely assume I will no longer be mentioning you by name at the Jessfield Park celebration. At least if I do, it will not be in a complimentary light …’

‘Mr Banks, please, listen to me. If you are determined to continue, despite the danger, then I cannot stop you. But you will undoubtedly be safer alone. With me, you certainly run the risk of being fired upon. You, on the other hand, are a white man in civilian clothes. As long as you are very careful, and announce yourself clearly before any encounter, it is possible you will come to no harm. Of course, I repeat my recommendation that you wait until the situation here is resolved. But then again, as someone myself with ageing parents, I can well understand your feelings of urgency.’

I rose to my feet and brushed off as much dust as I could. ‘Well then, I shall be on my way,’ I said coldly.

‘In that case, Mr Banks, please take this with you.’ He was holding out a small torch. ‘My advice, as before, is to stop and wait if you do not reach your destination by dark. But I can see from your present attitude you might well be inclined to push on. In which case, you will certainly need the torch. The batteries are not new, so do not use it any more than you need to.’

I dropped the torch into my jacket pocket, then thanked him somewhat grudgingly, already rather regretting my outburst. The dying man had now stopped trying to talk and was just screaming again. I had begun to walk towards the sound, when the lieutenant said:

‘You can't go that way, Mr Banks. You will have to move north for a while, then try to navigate yourself back on course later. Come this way, sir.’

For a few minutes, he led me on a path perpendicular to the one we had been taking. In time we came to another wall with a hole gouged out of it.

‘You should go this way for at least half a mile before turning east again. You may still meet soldiers, from either side. Remember what I told you. Keep your revolver hidden, and always announce your neutrality. If you encounter any of the inhabitants, ask them to direct you to the East Furnace. I wish you luck, sir, and I regret I cannot assist you further.’

*

After I had been moving north for several minutes, I noticed the houses becoming less damaged. This did not, however, make my journey any the easier; the roofs being more intact meant I had to make do with a much murkier light – I had decided to save the torch till nightfall – and I would often have to feel my way along a wall for some distance before coming across an opening. There was, for some reason, far more broken glass in this vicinity, and also large areas submerged in stagnant water. I frequently heard the scuttling of large groups of rats, and once trod on a dead dog, but could not hear any sounds of fighting.

It was at around this stage of the journey that I found myself thinking again and again of Jennifer, sitting in the prefects’ room on that sunny afternoon we had parted – and in particular, of her face as she had made that curious vow, uttered so earnestly, to ‘help me’ when she was older. Once, as I groped my way forward, an absurd picture came into my head of the poor child struggling after me through this ghastly terrain, determined to make good her promise, and I suddenly felt a rush of emotion that all but brought tears to my eyes.

Then I came upon a hole in a wall through which I could see only pitch blackness, but from which came the most overwhelming stink of excrement. I knew that to keep on course I should climb through into that room, but I simply could not bear the idea and kept walking. This fastidiousness cost me dear, for I did not find another opening for some time, and thereafter, I had the impression of drifting further and further off my route.

By the time it grew completely dark and I began to use the torch, I was coming across many more signs of habitation. I would often stumble into a barely damaged chest of drawers or shrine, even whole rooms in which the furnishings were hardly disturbed, giving the impression the family had just gone out for the day. But then right next to such places I would discover more rooms utterly destroyed or flooded.

There were, too, more and more stray dogs – scrawny beasts I feared might attack me, but which invariably shrank away growling when I shone my beam at them. Once I came upon three dogs savagely tearing something apart, and drew my pistol, so convinced was I they would come for me; but even these animals meekly watched me pass, as though they had come to respect the carnage a man was capable of wreaking.

I was not so surprised, then, when I came across the first family. I found them in my torch beam, cowering back into a dark corner: several children, three women, an elderly man. Around them were the bundles and utensils of their existence. They stared at me in fear, brandishing makeshift weapons, which they lowered only slightly at my words of reassurance. I tried to enquire if I was anywhere near the East Furnace, but they returned only uncomprehending stares. I came across three or four more such families in the nearby houses – increasingly, I was able to use actual doorways rather than openings in walls – but found them no more responsive.

Then I entered a larger space, the far side of which was bathed in the reddish glow of a lantern. There were a lot of people standing about in the shadows – again, predominantly women and children with a few elderly men among them. I had begun to utter my usual words of reassurance, when I sensed something odd in the atmosphere, and stopping, reached instead for my revolver.

Faces turned to me in the lantern glow. But then almost immediately the gazes returned to the far corner where a dozen or so children had crowded around something down on the ground. Some of the children were poking with sticks at whatever it was, and then I noticed that many of the adults were holding at the ready sharpened spades, choppers and other improvised weapons. It was as though I had disturbed some dark ritual, and my first inclination was to walk on past. Perhaps it was because I heard a noise, or perhaps it was some sixth sense; but I then found myself, revolver still drawn, moving towards the circle of children. The latter seemed reluctant to reveal what they had, but gradually their shadows parted. I then saw in the dim red glow the figure of a Japanese soldier lying quite still on his side. His hands were tied behind his back; his feet too had been bound. His eyes were closed, and I could see a dark patch soaking its way through his uniform under the armpit further from the ground. His face and hair were covered in dust and speckled with blood. For all that, I recognised Akira with no difficulty.

The children had started to gather round again, and one boy prodded Akira's body with a stick. I commanded them to get back, waving my revolver, and eventually the children retreated a little way, all watching carefully.

Akira's eyes remained closed while I looked him over. His uniform was torn away at the back, right down to his raw skin, suggesting he had been dragged along the ground. The wound near his armpit was probably caused by shrapnel. There was a swelling and cut on the back of his head. But he was so covered in grime, and the light was so poor, it was hard to ascertain how serious these injuries were. When I shone the torch on him, heavy shadows fell everywhere, making it even harder to see clearly.

Then, after I had been examining him for a few moments, he opened his eyes.

‘Akira!’ I said, bringing my face close. ‘It's me. Christopher!’

It occurred to me that with the light behind my head, I would appear to him no more than an intimidating silhouette. I thus called his name again, this time turning the torch beam on to my face. It is possible this action only served to make me look like some hideous apparition, for Akira grimaced, then spat contemptuously at me. He could not summon much force and the saliva dribbled down his cheek.

‘Akira! It's me! How fortunate to find you like this. Now I can help you.’

He looked at me, then said: ‘Let me die.’

‘You're not dying, old chap. You've lost some blood, and you've had something of a rough time of it lately. But we'll get you to some proper help and you'll be fine, you'll see.’

‘Pig. Pig.’

‘Pig?’

‘You. Pig.’ Again he spat at me, and again the spittle dribbled out of his mouth without force.

‘Akira. Clearly you still don't realise who I am.’

‘Let me die. Die like soldier.’

‘Akira, it's me. Christopher.’

‘I not know. You pig.’

‘Listen, let me get these ropes off you. Then you'll feel much better. Then you'll soon come to your senses.’

I glanced over my shoulder, thinking to demand some tool with which to cut his bonds. I then saw that all the people in the room had gathered in a crowd just a little way behind me – many holding weapons of one sort or another – as though posing for a sinister group photograph. I was somewhat taken aback – I had for the moment forgotten about them – and felt for my revolver. But just at that moment, Akira said with a new energy:

‘If you cut string, I kill you. You warn, okay, English?’

‘What are you talking about? Look, you blockhead, it's me, your friend. I'm going to help you.’

‘You pig. Cut string, I kill you.’

‘Look, these people here will kill you just as quickly. In any case, your wounds will become infected soon. You have to let me help you.’

Suddenly two of the Chinese women began to shout. One appeared to be addressing me, while the other was shouting to the back of the crowd. For a moment confusion reigned, then a boy of around ten emerged holding a sickle. As he came into the light, I could see a piece of fur – perhaps the remains of a rodent – dangling from the point of the blade. It struck me the boy was holding the sickle with such care so as not to let this offering drop, but then the woman who had shouted at me grabbed the sickle and whatever it was fell to the ground.

‘Now look,’ I stood up and cried at the crowd. ‘You've made a mistake. This is a good man. My friend. Friend.’

The woman shouted again, indicating I should step aside.

‘But he's not your enemy,’ I went on. ‘He's a friend. He's going to help me. Help me to solve the case.’

I raised the revolver and the woman stepped back. Meanwhile, everyone else was talking at once and a child began to cry. Then an old man was pushed to the front, a young girl holding his hand.

‘I speak English,’ he said.

‘Well, thank goodness for that,’ I said. ‘Kindly tell everyone present that this man here is my friend. That he's going to help me.’

‘Him. Japanese soldier. He kill Aunt Yun.’

‘I'm sure he didn't. Not him personally.’

‘He kill and steal.’

‘But not this man. This is Akira. Did anyone see him, this particular man, kill or steal? Go on, ask them.’

Rather reluctantly, the old man turned and muttered something. This provoked more arguing, and another weapon, a sharpened spade, was handed round and grasped by one of the other women at the front.

‘Well?’ I asked the old man. ‘Aren't I right? No one saw Akira personally do any wrong.’

The old man shook his head, perhaps to disagree, perhaps to indicate he had not understood. Behind me, Akira made a noise and I turned to him.

‘Look, you see? It's just as well I came by. They've got you mixed up with some other fellow, and they want to kill you. For God's sake, do you still not know who I am? Akira! It's me, Christopher!’

I took my eyes off the crowd, and turning fully to him, shone the torch into my face again. Then when I clicked it off, I saw for the first time the beginnings of recognition on his face.

‘Christopher,’ he said, almost experimentally. ‘Christopher.’

‘Yes, it's me. Really. It's been a long time. And not a moment too soon, it would seem.’

‘Christopher. My friend.’

Rising, I looked through the crowd, then gestured to a young boy holding a kitchen knife to come closer. When I took the knife from him, the woman with the sickle moved threateningly towards me, but I raised the revolver and shouted to her to keep her distance. Then kneeling down again beside Akira, I went about cutting his bonds. I had imagined Akira had said ‘string’ because of his limited English, but I now saw he was indeed tied with old twine that yielded easily under the blade.

‘Tell them,’ I said to the old man, as Akira's hands came free, ‘tell them he's my friend. And that we're going to solve the case together. Tell them they've made a big mistake. Go on, tell them!’

As I turned my attention to Akira's feet, I could hear the old man muttering something and arguments starting again in the crowd. Then Akira sat up cautiously and looked at me.

‘My friend Christopher,’ he said. ‘Yes, we friends.’

I sensed the crowd moving in and sprang to my feet. Perhaps in my anxiety for my friend, I shouted in an unnecessarily strident tone: ‘Don't any of you come any nearer! I'll shoot, I really will!’ Then turning to the old man, I cried: ‘Tell them to get back! Tell them to get back if they know what's good for them!’

I do not know what the old man translated. In any case, the effect on the crowd – whose belligerence, I now realised, I had much overestimated – was utter confusion. Half of them appeared to believe I wished them over by the wall to our left, while the remainder assumed I had commanded them to sit down on the ground. They were all of them clearly alarmed by my demeanour, and in their anxiety to comply, were stumbling over one another and shouting in panic.

Akira, realising he had to seize his chance, made an attempt to climb to his feet. I hoisted him up by his arm, and for a moment we stood swaying together unsteadily. I was obliged to tuck the revolver back in my belt to free my other hand, and we then tried a step or two together. A putrid smell was coming from his wound, but pushing this out of my mind, I shouted over my shoulder, no longer caring how many of them understood:

‘You'll see soon enough! You'll see you made a mistake!’

‘Christopher,’ Akira murmured in my ear. ‘My friend. Christopher.’

‘Look here,’ I said to him quietly. ‘We have to get away from these people. That doorway in the corner over there. Do you think you can manage it?’

Akira, leaning heavily on my shoulder, looked into the dimness. ‘Okay. We go.’

His legs appeared unhurt and he walked reasonably well. But then after six or seven steps together, he stumbled, and for a moment, in our efforts to keep from collapsing in a heap, we must have looked to the onlookers as though we were wrestling one another. But we managed to find a new arrangement, and recommenced our walk. Once, a small boy ran forward to hurl some mud at us, but was immediately hauled back. Then Akira and I were at the doorway – the door itself had disappeared – and staggered through into the next house.