The topic was "Something Found". I pondered that for a couple of days, then I wrote 500 very rambling words and quickly realised that I hated every one of them. Then it occurred to me that before you can find something, you first have to lose it. So I threw away the terrible 500 words and wrote about a man who kept losing his cell phone -- I was feeling a bit obsessive about cell phones because I'd just spent almost $2000 buying myself a new one and I was guarding it jealously. No way was I ever going to lose it or drop it in the toilet!

For no very good reason, I made the cell phone loser an archaeologist -- I'd just read a science fiction story about an archeological discovery on the moon, of all strange places, and so archeology was very much on my mind. Once I had the basic situation defined, everything else just fell into place all by itself, though I had to do a fair amount of research to discover just what happened in London towards the end of 1666. I also needed to find out exactly how certain specific archeological techniques were applied in the field. But finding things out is always fun, so that was no hardship.

"Has anybody seen my cell phone?"

David’s father sounded amused rather than angry. He was constantly putting his cell phone down and then forgetting where he’d left it. The question he’d just called out to all and sundry was one that they were all quite used to hearing.

David’s father was an archaeologist, and during the long summer vacation from school David liked to work with him, helping him with whatever his latest project happened to be. This year his father was busy excavating a Roman villa in the heart of London. Some workmen had uncovered traces of it as they were preparing the site for a new shopping complex and, understandably, they were rather annoyed at having to stop work in order for the remains of the villa to be properly explored. Because there was a lot of pressure on them to get the excavation finished as soon as possible, David, his father and the rest of the team were working very long hours indeed.

As it happened, David knew exactly where his father’s cell phone was. He’d picked it up and slipped it into his backpack when nobody was looking. David wasn’t allowed a phone of his own because of some convoluted parental reason that he neither understood nor agreed with, so he was in the habit of taking advantage of his father’s absent mindedness whenever he got the opportunity.

Although David was studying maths, physics and chemistry for his A-Levels at school, he was nevertheless very fond of history, and watching history come alive as his father excavated it was a never ending delight. This year he was finding the experience particularly thrilling. He’d never been involved in exploring anything this old before.

His father strode back down into the trench and soon forgot all about his missing cell phone as the excitement of the dig grabbed hold of him again. "Come and take a look at this," he called out to David. He was pointing at a thick, black layer that ran along the wall of the trench.

"What is it?" asked David.

"Ash," said his dad. "Ash from a fire. Because this stratum is so thick and because it runs for such a long way, I’m pretty sure that it must date from the great fire of London in 1666. What we are seeing here are the remains of the buildings that were destroyed in the blaze." He poked at the ash with his trowel and a section flaked away, exposing a piece of broken pottery. "I’d really like to examine this layer more closely," he continued. "Who knows what we might find? This part of London is very close to Pudding Lane, where the fire started. There could be all sorts of useful and informative artefacts buried right here in this layer."

"We don’t have time, dad," said David. "The Roman villa is more important. We need to work on that."

His dad sighed. "You’re right," he agreed, and he walked down to the end of the trench where a rather delightful Roman mosaic floor was slowly being exposed to the light of day for the first time in more than 1,500 years. The mosaic was in a very delicate condition. The grouting had decayed away and the only thing holding it together was the soil in which it was embedded. The team had glued hessian cloth to the surface so as to hold the tiles together. Now they were digging into the soil beneath the mosaic and sliding in wooden boards for the tiles to rest on. When that was done they would lift each board out of the trench and take it to the studio of an expert conservator who would have the daunting task of fitting the whole jigsaw puzzle back together again. It was slow, painstaking work and David wasn’t allowed to help with it. "Teenagers are too clumsy and impatient," said his father.

David was intrigued by the evidence of the great fire that they’d discovered. He’d vaguely heard about it, but he didn’t know any of the details, so he used his father’s phone to look it up. Wikipedia told him that the fire had started shortly after midnight on the 2nd of September 1666 in the bakery of Thomas Farriner in Pudding Lane. It had burned out of control for four days, completely destroying much of the area inside the old Roman city walls. Presumably one of Farriner’s ovens had malfunctioned, but since both the bakery and Thomas Farriner himself were utterly destroyed in the inferno, nobody had ever been able to confirm that.

David studied the map that was included in the Wikipedia article. The place that used to be Pudding Lane was indeed less than a minute’s walk from the archaeological dig. Well, well thought David, what a perfect opportunity. He returned the phone to his backpack and pulled out the time machine he’d built in the physics lab at school when nobody else was around. He’d never told anyone about it. After all, he was a teenage boy. He communicated mainly with grunts, gestures and rolled eyeballs. Most people spent most of their time pretending that he wasn’t there, so it wasn’t hard for him to keep his time machine secret.

In the blink of an eye he found himself standing in London an hour or so before the fire was due to start. He walked down Pudding Lane. Thomas Farriner’s bakery was easy to find. It was the only building with a light showing. A delicious smell of baking bread wafted down the street from it, almost obscuring the mingled smells of horse, and human, excrement. David knocked on the door. Nothing happened, so he thumped it harder. Eventually the door creaked open and a small, suspicious man peered out. "What?" he snapped.

"Thomas Farriner?" asked David.

"Yes," said the baker. "Who wants to know? Hurry up. I’m a busy man. There’s something wrong with one of the ovens. I just can’t get the damn thing to start burning."

"I can help you with that," said David.

He took a small box out his pocket and shook it in Thomas Farriner’s face. It rattled, and Farriner took a startled step backwards. "What’s that?" he asked.

"It’s a box of matches," said David. "They are self-igniting. You’ll be able to get the oven alight in no time with these, you mark my words. There’s nothing like a box of matches for starting a fire!"

"Matches?" said Farriner, sounding puzzled. "What are matches?"

"I’m sure you’ll manage to work it out," said David confidently. He pushed the box of matches into Farriner’s hand and then turned to leave. "Just remember to rub them on the rough side of the box," he called out over his shoulder.

As soon as David heard Farriner close the bakery door behind him, he activated his time machine and returned to his father’s archaeological dig. He gazed thoughtfully at the line of ash in the trench wall. He ran his finger along it, enjoying the rough feel of the charcoal. There was no overt evidence that he had been responsible for it. Maybe Farriner’s oven would have started burning the city down without his help. But the tingle he got from thinking that he might actually have caused the great fire of London felt really good.

"Where’s my cell phone," roared his father from the end of the trench, breaking the spell that held David transfixed. "Has anybody seen my cell phone? I need to call the conservator. This section of the mosaic is collapsing."

David could see that his father had dug a bit too deeply under one section of the mosaic and the tiles were starting to fall into the hole. He looked at his father’s phone sitting beside the time machine in his backpack and he smiled as a delicious idea occurred to him. He used the time machine again...

The mosaic was still being built. It was less than half complete. The tiles were bright and colourful. Despite himself, David was impressed. These Roman artists were hugely talented. One of the artisans looked up as David approached. "Loquerisne latine?" he said. "Do you speak Latin?" Clearly he felt that David was a little out of place, though he didn’t seem to notice that David was a long way out of time as well!

David grunted, shook his head and rolled his eyeballs. The man frowned. "Quis es?" he said. "Who are you? Quid vis? What do you want?"

David ignored him and the man started to get up, but then one of his colleagues called him over for help and he returned to work. David breathed a sigh of relief and while nobody was looking, he slipped his father’s cell phone beneath the section of the mosaic that would collapse into the hole that his father’s trowel would dig 1,500 years in the future. Then he returned to his father before any more of the mosaic builders got too interested in him.

"Haven’t you found your cell phone yet dad?" he asked.

His father shook his head angrily. "No," he said, "I haven’t."

He sounded frustrated and David didn’t blame him. After all, in one very real sense, his father hadn’t been able to find his cell phone for at least 1,500 years. "What’s that," asked David, pointing to something that was just peeping out from beneath the tiles. "It looks like the edge of a cell phone to me."

His father looked surprised and then carefully started to brush away the soil. Slowly the cell phone revealed itself. The years had not been kind to it. It was cracked and bent, warped and distorted by the pressure of the earth it had lain beneath for so long. Nevertheless it was still recognisably his father’s cell phone. Plastic is almost indestructible. "I didn’t know the Romans had cell phones," said David, innocently.