It was the sort of frosty spring morning that children reveled in after a long winter, and as likely as not would lead to sore throats and runny noses, for spring had only just peaked its head up to entice youngsters outdoors to play when winter had not quite let go of his grip over the park. It was sunny, and the less shy flowers had already stuck up their heads and all the trees that weren't in full leaf were certainly considering it, and birds were warbling for their true loves and some had already begun the satisfactory practice of nesting.

Bert should have been a sweep that day, for it was exactly the sort of day that sweeps were in demand; chilly enough that people wanted their fires but not so chilly that they were willing to put up with the smoke, and many a person would decide now was the perfect time for a bit of cleaning. It was a fine day though, and one of the perks of being Bert was picking and choosing what he wanted to be, and on this day he wanted to be an artist. So he buttoned up his coat against the frosty chill, gathered his chalk, and strolled to the park where he hoped to earn a coin or two, or at least to enjoy the day immensely.

He did find a crowd, but mostly children who tended to pay him in compliments and interest rather than coins. He said hello to those he knew, and then to those he didn't because it was that sort of pleasant morning. Children liked to gather around Bert (and so did adults, but they pretended they had some other purpose to be there) because once they got him talking, Bert would share the most marvelous stories, or teach them the funniest songs. If they really got him going, they might even get a bit of dancing, and that was the best of all.

This was not a singing and dancing sort of morning, and most of the children were too caught up in releasing all the energy the winter had forced them to restrain, and so only came over for a moment to admire his artwork, say hello, and then run off again. Michael Banks stayed the longest, long after his sister had lost interest (once she was sure there was no chance of jumping into the art). It seemed the boy had developed a real interest in drawing and wanted to know how Bert could get a picture to come out so clearly with just a few strokes of chalk.

"Is it magic?" he asked.

"All art is magic," Bert answered promptly. "Didn't you know? It's taking what's inside and showing it to the world."

Then Michael was absolutely thrilled when Bert let him have a go with his chalk, a very rare honor, for chalk might be cheap but Bert could ill afford to lose his supply at the rate all the children of the park would use it up.

Michael very clearly felt his privilege, and set about to create the most wonderfully magic masterpiece that his youthful skill could create. Bert let him at it, after he'd given his pointers, and it was so amusing to watch the boy imitating his own quick strokes, tongue stuck out in concentration and a happy glow about his face, that Bert almost forgot about getting on with his own work. He did, of course, both in the hopes of enticing money into his hat and to allow Michael his secrets, for Michael clearly wanted to wait until he was done to share his work. When Jane came over to see what they were doing, he practically threw himself over his picture, coming close to smudging it in his haste to cover it up.

"You will show me when it's done, won't you?" Jane asked, her eyes alight with curiosity. She didn't ask for her own chalk, though. Bert wasn't sure if it was disinterest or a sort of sisterly sense that this was Michael's special space. He'd have let her if she'd asked. Instead she wandered off to look for the hidden secret blossoms hiding about the park and Michael finished his drawing.

Only, just as Michael leapt up, his face aglow with accomplishment, before going all anxious and shy as he clearly worked himself up to sharing his art, there came a great ruckus across the park.

"Here you!" shouted an angry man's voice, and before Bert or Michael knew what was happening, a boy ran right down the middle of their art. That was bad enough, but he was also covered head to toe in soot, and barefoot besides, which was worse than shoes for smudging chalk. And, almost as though the boy sought to do the most damage possible, he startled into skidding to a stop at the sight of Bert and Michael's shocked faces. And the skid slid right across Michael's work.

What had been a decent, if untrained attempt at a sunset over London's rooftops (the lines were quite wobbly but the contrast of light and dark was surprisingly effective), was now a sooty smear across the bottom and with a great black footprint right over the brightest bit of the sun.

Bert's work wasn't much better, what wasn't now covered in footprints or smudged was sprinkled liberally with soot from the boy's run.

Now Bert was not one to begrudge a person some good clean soot. Nor was he one to look down on a boy for being barefoot or having threadbare (and dirty) clothes. And while having a few hours' worth of work demolished in a moment was pleasant for no one, Bert understood that accidents happened, particularly when the one committing the mishap was a child.

What he did not appreciate was a complete lack of manners. Not a single 'sorry' did the intruder utter. Not even an 'oops'. He looked down at his calamitous handiwork, or rather, footwork, and he laughed.

And then the man who had shouted 'Here, you!' Shouted from much closer, "You dirty little ragamuffin! Just you wait 'til I get my hands on you!"

And still smiling as though he'd done something clever, the boy took off once more.

To give him some credit, he didn't complete his path across the artwork, but that could well have had to do with Bert and Michael, the first who was frowning and the second whose shocked expression was morphing into something approaching murderous, who he'd have had to run right by. Instead he ran over the grass, pursued by a large, lumbering man in a fine waistcoat who looked far too red in the face to be healthy…except for the streaks of black soot that made him look quite fierce. Certainly the boy didn't wait to be caught.

Once the scene had passed, both artists looked at their hard work. Of course, Bert was used to seeing his work destroyed; that was the nature of chalk art after all, but Michael was absolutely devastated.

"Oh no," said Jane, who had of course seen the whole commotion and had come over to join them. "And it has such wonderful colors, too."

"Hey, now," said Bert, "This isn't the end of the world. Why, this could be a new style of art! Look how realistic the soot captures the…er…" He wasn't entirely sure what Michael's picture was supposed to be. And Michael was not consoled in the least.

"Sunsets don't have soot," he said, his voice thick with what he'd insist was rage, but probably had as much to do with the way his eyes were shimmering.

"Well, and why shouldn't they?" Bert asked. "Why, sometimes mistakes like these are just the thing you need to make something wonderful and new!"

"Mistakes?" Michael demanded. "He laughed! He was glad he did it."

This seemed all too true to be denied, and for a moment Bert was stumped. Then he brightened and said, "Well, you will just have to make a new picture."

"We haven't time," Jane said, her voice filled with sympathy and regret. "We're expected home soon."

"And who says you can't finish your work at home?" Bert asked. Michael's eyes stopped shimmering at that, for the very idea confused him, and confusion will turn away tears every time.

"But…we can't take the pavement and chalk into the house," he said, "…can we?"

"Not the pavement maybe, but the chalk, why, nothing easier! Just you find yourself a bit of paper, and the next time we see each other you can show it to me. And it won't wash away with the next rain!"

"You mean…I can have some chalk to take home just for me?" Michael asked, his voice alight with surprise and hope.

"Of course you can," said Bert. "We aspiring artists need to help each other out, don't we?"

"Is Michael an artist?" Jane asked with great astonishment. Clearly Bert was an artist…but her little brother?

"Anyone with that much feeling inside could be nothing else," Bert answered. Which the children didn't entirely understand, but they accepted anyway.

"But what a horrible, dirty little boy," Jane remarked, looking in the direction he had run. They could still see sooty footprints all across the grass.

"I hope that mean old man does catch him and…and…" but Michael couldn't quite figure out what horrible fate he wanted to wish on the boy.

"Hey now, no need for that," said Bert, who, in spite of everything, rather hoped the boy wasn't caught. Even if he deserved something.

"Well, he should have to go to his room with no supper," Jane declared decisively.

As Bert had rather more experience than Jane in children who do not have a banker for a father, he rather feared that Jane's punishment might well be in the boy's future, and too many days of his past, but just then didn't seem to be the time to bring it up. Instead, he carefully helped Michael pick out the colors he absolutely needed for his art. Michael was so careful in his choosing only exactly what he needed, in fact, that Bert found himself shoving half a dozen more into his hands 'just in case'.

"And you will show me the finished work?" Bert asked.

"When it's finished," Michael promised.

Both children left with smiles on their faces, and Bert smiled to watch them go. Then he looked back at his own ruined art, and the frown returned. He knew most of the children who came to this park, from all walks of life, but he didn't know that boy and he rather wished he did.

A boy like that, clearly up to mischief and with no concept of manners or compassion or…or respect for other people's hard work, clearly needed to be taken in hand. Bert was only human, after all, and though he'd steered Michael and Jane away from their wishes for revenge, in his heart he did hope he'd cross paths with the boy again so that he could teach him a lesson or two. He wouldn't be cruel (certainly nothing physical, as the pursuing man clearly intended). And he'd never deny anyone a meal, as Jane had suggested. A little intimidation certainly wouldn't hurt the boy, though, and was less than he deserved. Perhaps a bit of labor and a tongue lashing would teach him to laugh at ruining other people's work.

In fact, the boy may well have done Bert a favor. Several of the park's inhabitants were sorry enough about the whole mess that Bert probably got more coins out of them than their appreciation of the art would have done.

He did follow the sooty footprints later, once he'd fixed what he could (he wasn't lying to Michael about using the ruin to create something new) and picked up his chalk and his hat, but he lost the path long before he found the boy. He didn't see the angry man again either.

In the end, he shrugged, then went to fetch his bicycle. It was about time to don his leerie hat and light the streets of London. Rude little art vandals would have to wait for another day.