Marching, constantly marching. From sunrise to sunset, we were made to walk, chained together like animals and subjected to constant bullying from our captors, who were quite clearly strangers to personal hygiene. After nearly a week on the road, my clothes were dusty and travel-stained and I found myself wishing I could escape from here, return to the TARDIS and leave Roman times for good. This was meant to be a holiday - and we had spent much longer in this time period than usual - but one thing I had learned about the Doctor was that we would inevitably run into trouble sooner or later. This time, trouble had come in the form of two slavers, Sevcheria and Didius, who had come to the villa where we had been staying and dragged Ian and myself away. Luckily, the Doctor and Vicki were not at the villa, the Doctor having decided to take a trip to Rome and Vicki having offered to accompany him; otherwise, they would have been captured too.

I looked down at the Roman dress I was wearing, recalling how, when I first put it on back in the TARDIS's wardrobe room, I had studied my reflection in the mirror. I thought then that it gave me an air of dignity, reminding me of an illustration of the goddess Minerva in a book on Roman mythology I had as a child. Right now, however, I felt distinctly ungoddess-like. If "ungoddess-like" is even a word . . .

"Up! Get up, you worthless lump!"

A shout from Sevcheria distracted me from my thoughts. I looked ahead to see that one of the other slaves, a woman, had fallen and was now sprawled in the dirt. She was coughing rather heavily and I wondered if I should do something to help her. Since that business with the Aztecs, I had learned the hard way that there was only so much we as time-travellers could do, that some things were inevitable no matter what anyone did to try and change things. But, as Sevcheria raised his whip to strike the unfortunate woman, I knew I could not let this happen. I could not just stand by and watch someone get beaten just for being too exhausted to continue.

"Stop!" I shouted, putting as much authority into my voice as I could given my current circumstances. For a moment, I imagined that I was back at Coal Hill School, dealing with a playground bully. Startled, Sevcheria stopped in mid-swing and turned in my direction. Clearly, he had not expected to be challenged by a mere slave. But I was no "mere slave"; I was Barbara Wright, a history teacher from 1963 and, since my curiousity about one of my pupils (a girl named Susan Foreman) led myself and my colleague, Ian Chesterton, into what seemed to be an ordinary police box but was really something completely different, a traveller in space and time. And, if there's one thing I can't stand, it's watching others suffer.

I glared at Sevcheria. "Can't you see she's too exhausted to keep going?" I demanded, nodding towards the fallen woman.

"Is that so?" Sevcheria said, striding over to me. "Then perhaps you'd like to take her share of the lash." With that, he drew back his arm and gave me a stinging slash across the back, swiftly followed by four more. Determined not to give this bully the satisfaction of seeing me flinch, I took the blows in silence and told myself that it was better that I, and not that poor woman who had fallen, was receiving them.

When he was through, Sevcheria marched away. He was always careful not to overdo it when he had to discipline slaves, though I knew he was not acting out of concern for our welfare, but out of a need to ensure that we reached the slave market in a reasonably saleable condition. I was, in essence, a commodity to be bought and sold, a piece of property.

Sevcheria then turned to his fellow slaver. "Right, Didius," he said. "We'll rest here for a while. See that the slaves are secured."

As Sevcheria and Didius moved among the slaves, Didius distributing hunks of rough bread while Sevcheria gave mouthfuls of water from a leather bag, I recalled how, a few years before I got involved with the Doctor, I had been to see Ben Hur at the cinema. If someone had told me then that I would one day experience life as a Roman slave for myself, I wouldn't have believed them. Now, however, things were different; I'd visited the past and the future, but the Doctor seemed to be incapable of getting Ian and I back to our own time. The one time he succeeded, something went wrong and the TARDIS was miniaturized, along with everyone inside.

Once I had been given my "rations", a word I would always associate with my wartime childhood, I turned to the woman who had fallen earlier, wondering if I could do something for her. Not that there was much I could do, but I hoped I might at least be able to comfort her. I've always been a very compassionate person; once, when I was helping a caveman who had been attacked by an animal, Ian joked that I must have a flat full of stray cats and dogs. Actually, I'd never had a dog in my life and the last time I'd had a cat was when I was a teenager . . . Anyway, I felt I had to do what little I could for this woman.

"Are you all right?" I asked her.

She looked up. I hadn't had chance to look at her closely before, but I suddenly realised that she was still quite young, probably around my age, though it was hard to tell. "Yes," she replied, her voice sounding somewhat hoarse. "The dust from the road gets in my throat, that's all." She coughed and, looking at her, I was shocked to realise just how ill she looked. If she got any worse, I knew Sevcheria would decide she was useless, not worth keeping alive. I had seen him deal with a slave who was too weak to continue before; a man had collapsed from exhaustion and, when the whip failed to force him to his feet, Sevcheria simply ran the unfortunate man through with his sword.

For now, though, I was determined to do what little I could for this woman; if nothing else, I could at least provide her with company. Being a slave en route to market was a very lonely experience, even though I was never physically alone. I thought of everyone I knew - my friends and family back in my own time, wondering if I would ever see them again; the Doctor's granddaughter, Susan (the same Susan about whom Ian and I were so curious) now living in the 22nd Century and helping to rebuild the world after a Dalek invasion; the Doctor himself, a mysterious and somewhat tetchy old man who travelled in a time machine disguised as a police box and had never revealed who he was or exactly where he came from; Vicki, the young girl we had rescued from the planet Dido and who had quickly filled the gap left by the recent departure of Susan; Ian . . . I paused, recalling how he and two other male slaves had been bought not long after we were captured. He had promised that he would meet me in Rome, but I had no way of knowing where he had been taken or what was happening to him now.

"Come on," I said to the woman, noticing that she had not eaten her hunk of bread, "you must eat."

She looked down at the bread she was clutching in her hand. "I - I can't. The crust sticks in my throat." She coughed again.

"At least try - you need to keep your strength up." As I spoke, I remembered a time when, as a little girl, I was ill and didn't feel like eating. My mother had said exactly the same words to me as I had just said to this poor woman.

Somehow, the woman managed to choke down the bread. "Where do you come from?" she asked me when she had finished.

"Londinium," I told her, using the Roman name for the place which I know as London. I decided it was best if I didn't tell her the whole truth about myself, in particular the fact that I came from nearly 2000 years in her future. "It's a town in Britannia," I continued. "Have you heard of it?"

She shook her head. "I saw them bring you," she said, nodding in the direction of Sevcheria and Didius. "You and that young man, one of the three who was sold."

"That's Ian," I replied. "A friend of mine - he said he'd try to find me when we get to Rome." At least I hoped he would, but, like I said before, I did not know if he would be able to keep that promise. As a history teacher, I know something about what happened to slaves in Roman times, so I knew that, though there was a chance that the man who had bought Ian and those other two slaves had simply wanted some domestic help in his villa, there was also a chance that, since they were three strong young men, they had been put to work rowing in a galley, digging in a quarry or some other task which required a great deal of muscle power.

But at least I could hope. And at least I could be grateful that the Doctor and Vicki were still free, though I couldn't help wondering what they would think when they returned from their trip to Rome and found the villa empty. Would they wait for us and, if so, how long would it be before they gave us up for lost, got into the TARDIS and went off to some other time or planet? Somehow, I would have to find a way to escape and hope Ian was able to do the same.

"By the way, I'm Barbara," I told the woman. "What's your name?"

Before she could reply, Sevcheria appeared. "Right!" he barked at us. "Rest period's over! On your feet!"

There was a collective groan from the slaves, but we forced ourselves to stagger to our feet and I helped the woman up. We all knew what would happen to us if our captors thought we were too weak to continue.

Eventually, we reached Rome and were herded unceremoniously into cells, where we would remain until we were sold in the market. Most of us, at least; I was told shortly before I was sold myself that the woman I had been looking after was only fit to be taken to the circus. And I knew a Roman circus was not something which involved clowns, or acrobats, or elephants in fancy plumed headdresses, or any of the other things I, as a person from the 20th Century, associated with circuses.

Anyway, I became a maidservant to Poppaea, the wife of the Emperor Nero, though I seemed to spend a great deal of my time evading Nero's amorous advances. However, I found an ally in Tavius, the court slave-buyer, who showed a degree of altruism that was rare in his time. He helped reunite me with Ian (who, along with another slave, managed to escape after the galley they were on went down in a storm, only for both of them to be arrested as fugitives and forced to train as gladiators) and we were able to use the confusion caused by the Great Fire of Rome to flee back to the villa.

And that was where we were when the Doctor and Vicki returned from Rome, in the villa, where we had been idling our days away. Or so the Doctor thought . . . And I later learned that he and Vicki had been in Nero's palace at the same time I was, though I was unaware of this at the time. In any case, we decided that it was time to leave, time to move on to our next adventure.

Since then, I've tried to avoid thinking about the unfortunate woman I met because I know that, even if the TARDIS did materialise in Roman times again, there would be nothing we could do to save her from her ultimate fate; the Doctor would call that "interfering with history". I did what I could for her - my conscience wouldn't have allowed me to do otherwise - and, had we been able to rescue her at the time, we might have at least tried to do so. Now, however, it's too late. Even if she survived the Great Fire, she would eventually have been thrown into the arena to be torn apart by lions or some other wild beasts for the "entertainment" of the crowds.

And I never even knew her name.