"How much is the glass statue?" the impossibly young and innocent Steve Leopard asked, pointing to a statue on my tray which you could eat. Shakily, fighting to keep my hand steady, I showed him the price tag. "I can't read," Steve said. "Will you tell me how much it costs?"

I noted the look of surprise on Darren's – Charna's guts! – on my face. Steve had guessed straightaway that there was something strange about the Little People, but I hadn't been so sharp. The young me had no idea why Steve was lying.

I shook my head quickly and moved on, leaving Steve to explain to my younger self why he'd pretended he couldn't read. If I'd been feeling light-headed earlier, I felt positively empty-headed now. It's a remarkable, earth-shattering thing to look into the eyes of a youthful you, to see yourself as you once were, young, foolish, gullible. I don't think anyone ever remembers what they were really like as kids. Adults think they do, but they don't. Photos and videos don't capture the real you, or bring back to life the person you used to be. You have to return to the past to do that.

We finished selling our wares and headed backstage to collect fresh trays full of new items, based on the next set of performers – Truska, Hans Hands, and then, appearing like a phantom out of the shadows of the night, Mr Crepsley and his performing tarantula, Madam Octa.

I couldn't miss Mr Crepsley's act. When Jekkus wasn't looking I crept forward and watched from the wings. My heart leapt into my mouth when my old friend and mentor walked on to the stage, startling in his red cloak with his white skin, orange crop of hair and trademark scar. Seeing him again, I wanted to rush out and throw my arms around him, tell him how much I missed him and how much he'd meant to me. I wanted to say that I loved him, that he'd been a second father to me. I wanted to joke with him about his stiff manner, his stunted sense of humour, his overly precious pride. I wanted to tell him how Steve had tricked him, and gently wind him up for being taken in by the pretence and dying for no reason. I was sure he'd see the funny side of it once he stopped steaming!

But there could be no communication between us. Even if I'd had a tongue, Mr Crepsley wouldn't have known who I was. On this night he hadn't yet met the boy named Darren Shan. I was nobody to him.

So I stood where I was and watched. One final turn from at the vampire who'd altered my life in so many ways. One last performance to savour, as he put Madam Octa through her paces and thrilled the crowd. I shivered when he first spoke – Id forgotten how deep his voice was – then hung on his every word. The minutes passed slowly, but not slowly enough for me – I wanted it to last an age.

A Little Person led a goat on stage for Madam Octa to kill. It wasn't the Little Person who'd been with me in the audience – there were more than two of us here. Madam Octa killed the goat, then performed a series of tricks with Mr Crepsley, crawled over his body and face, pulsed in and out of his mouth, played with tiny cups and saucers. In the crowd, the young Darren Shan was falling in love with the spider – he thought she was amazing. In the wings, the older Darren regarded her sadly. I used to hate Madam Octa – I could trace all my troubles back to the eight-legged beast – but not any longer. None of it was her fault. It was destiny. All along, from the first moment of my being, it had been Des Tiny.

Mr Crepsley concluded his act and left the stage. He had to pass me to get off. As he approached, I thought again about trying to communicate with him. I wasn't able to speak, but I could write. If I grabbed him and took him aside, scribbled a message, warned him to leave immediately, to get out now…

He passed.

I did nothing.

This wasn't the way. Mr Crepsley had no reason to trust me, and explaining the situation would have taken too much time – he was illiterate, so I'd have had to get somebody to read the note for him. It might also have been dangerous. If I'd told him about the Vampaneze Lord and all the rest, he might have tried to change the course of the future, to prevent the War of the Scars. Evanna had said it was impossible to change the past, but if Mr Crepsley – prompted by my warning – somehow managed to do so, he might free those terrible monsters which even Mr Tiny was afraid of. I couldn't take that risk.

"What are you doing here?" someone snapped behind me. It was Jekkus Flang. He poked me hard with a finger and pointed to my tray. "Get out there quick!" he growled.

I did as Jekkus ordered. I wanted to follow the same route as before, so that I could study myself and Steve again, but this time the other Little Person got there before me, so I had to trudge to the rear of the theatre and do the rounds there.

At the end of the interval Gertha Teeth took to the stage, to be followed by Sive and Seersa (the Twisting Twins) and finally Evra and his snake. I retreated to the rear of the theatre, not keen on the idea of seeing Evra again. Although the snake-boy was one of my best friends, I couldn't forget the pain I'd put him through. It would have hurt too much to watch him perform, thinking about the agony and loss he was to later endure.

While the final trio of acts brought the show to a close, I turned my attention to the objects stitched into the lining of my robes. Time to find out what Evanna had sent me back with. Reaching underneath the heavy blue cloth, I found the first of the rectangular items and ripped it loose. When I saw what it was, I broke out into a wide toothless smile.

The sly old witch! I recalled what she'd told me on the way from the Lake of Souls to Mr Tiny's cave – although the past couldn't be changed, the people involved in major events could be replaced. Sending me back to this period in time was enough to free my soul, but Evanna had gone one step further, and made sure I was able to free my old self too. Mr Tiny knew about that. He didn't like it, but he'd accepted it.

However, working on the sly, unknown to her father, Evanna had presented me with something even more precious than personal freedom – something that would drive Des Tiny absolutely cuckoo when he found out how he'd been swindled!

I pulled all the other objects out, set them in order, then checked the most recent addition. I didn't find what I expected, but as I scanned through it, I saw what Evanna had done. I was tempted to flick to the rear and read the last few words, but then decided I'd be better off not knowing.

I heard screams from within the theatre – Evra's snake must have made its first appearance of the night. I didn't have much time left. I slipped away before Jekkus Flang sought me out and burdened me with another tray. Exiting by the back door, I sneaked around and re-entered the cinema at the front. I walked down the long corridor to where an open door led to a staircase – the way up to the balcony.

I climbed a few steps, then set Evanna's gift down and waited. I thought about what to do with the objects – the weapons. Give them to the boy directly? No. If I did, he might use them to try to change the future. That wasn't allowed. But there must be a way to get them to him later, so that he could use them at the right time. Evanna wouldn't have given them to me if there wasn't.

It didn't take me long to figure it out. I was happier when I knew what to do with the gift, because it also meant I knew exactly what to do with young Darren.

The show ended and the audience members poured out of the theatre, eagerly discussing the show and marvelling aloud. Since the boys had been sitting near the front, they were two of the last to leave. I waited in silence, safe in the knowledge of what was to come.

Finally, a frightened young Darren opened the door to the stairway, slipped through, closed it behind him, and stood in the darkness, breathing heavily, heart pounding, waiting for everyone to file out of the theatre. I could see him in spite of the gloom – my large green eyes were almost as strong as a half-vampire's – but he had no idea I was there.