Avery and Zib exchanged a look. This was going to be more difficult than they had expected.
“How can you be improbable on purpose?” asked Avery.
“I don’t know,” said Quartz.
Zib frowned. Zib sat down in the middle of the road and began picking at her hair, dislodging leaves and twigs and a small, startled lizard that had been there since she’d fallen out of the first tree.
“Get up,” said Avery. “We have to keep walking.”
“No,” said Zib. “I don’t think we do.”
“What do you mean?”
Zib got back to her feet. “I think it’s probable that if you follow a road, you’ll wind up going where the road goes. So that means that if you don’t follow the road, it’s improbable that you’ll wind up going where the road goes. So that means that if we want to follow the improbable road, we can’t follow it at all. Come on, Avery!”
She grabbed the boy’s hand and broke into a run, dragging him off the road and into the meadow on the other side. A wall of thorns burst from the ground behind them, cutting them off from Quartz and from the road.
Quartz smiled.
“Well,” he said. “That took them long enough.” Whistling, he began strolling onward, toward the distant, unseen spires of the Impossible City.
FOUR
THE CROW GIRL
Avery was not very fond of running. They did running three times a week at school, and he was always one of the very slowest, circling the track behind the rest of his class, lungs burning and legs aching and shoes pinching his feet. All those things happened now, as he ran with Zib. His breath whistled in his throat, which seemed to have gotten somehow smaller, forgetting what it was supposed to do. His legs were too long and too short at the same time, and his shoes hurt his feet, making him utterly aware of every single toe.
And he was laughing.
It seemed strange that he should laugh while he was being dragged across a meadow by a girl he’d only barely met and who wasn’t at all the sort of friend he was invited to bring home for lemonade and cookies. His mother would have sniffed at Zib’s hair, and his father would have scowled at Zib’s clothes, but here they were together, having an adventure, and he knew, deep down, that as long as she held on to his hand, he would be just fine.
He was still marveling over this impossible truth when his foot hit a stone and he went sprawling, his hand yanked from Zib’s by gravity. The grass, which had seemed dry when they were running across it, had pulled the trick beloved of grasses everywhere and hidden its wetness away down among its roots: as soon as Avery fell, he began to slide, slowly at first, then with growing speed, as his weight pressed the wetness out of the grass and into the soil beneath him.
The mud was candy-striped, pink and blue and purple, streaked with veins of golden glitter. Avery was too busy shrieking to appreciate it.
“Avery!”
Zib had been happy running through the meadow with her strange new friend beside her. Unlike Avery, she had always seen the value in being able to run faster than anyone expected, and she had been so delighted with her own cleverness that it had never occurred to her that he might feel differently. Now, watching him wheeze and yell as a sudden cascade of colorful mud carried him away, she wondered whether it might not have been a good idea to go a little slower.
There was a plopping, cascading sound. Zib ran along the stream of mud, which was swelling so that she thought soon it might be better to call it a river, and stared in horror as she saw what was happening: the mud was pouring over a cliff, and soon, Avery would pour over the cliff too.
“Avery, swim!”
Avery stopped thrashing as he turned and gave her a wide-eyed, open-mouthed look. “It’s mud!”
“I noticed!”
“I can’t swim in mud!”
“Why not? Try!” The cliff was getting closer. Zib couldn’t decide whether telling him would be a good thing—a motivation—or a bad thing, since no one really likes to hear that they’re about to be swept over a cliff and maybe drowned in mud.
Avery, to his credit, tried. He kicked his legs and flailed his arms, and all he managed to do was go under the mud, disappearing for one heart-stopping moment before he bobbed back to the surface, choking and coughing, with blue and purple streaks on his face. “I can’t!” he wailed.
Zib ran alongside the river of mud—when had it become wide enough for her to think of it as a river? This wasn’t improbable, this was impossible, and her heart rebelled from it even as her mind began looking for ways to make it go away—and considered her options as quickly as she could. If she dove in, they could both be swept over the cliff. She didn’t know Avery very well. Maybe she could find the Impossible City without him. The mud looked soft; he would probably be fine.
But then she would always, forever, be the kind of person who didn’t dive in when she saw that a friend who had made a little, simple mistake was being swept away by consequences he could never have predicted. She would walk in the shadow of that decision for the rest of her life. She would see that person in the mirror.
Zib took a deep breath, kicked off her shoes, which had never fit that well in the first place, and threw herself into the river of mud.
Avery had been right about one thing: it was difficult to swim in the mud. Zib, who had spent substantially more time in mudholes and ditches than he had, thought there was something strange about that; normally, moving through mud was a little difficult but not altogether impossible. This mud was almost like thin taffy. It grabbed at her arms and legs, pulling them down, keeping her from getting any sort of traction. She fought against it all the same, and reached Avery, grabbing hold of his wrist, barely a second before the river of mud carried them both over the cliff.
The mud roared as it slid around them. The mud thundered. Zib, who had never considered the voice of the earth, screamed. Mud flowed into her mouth. She screamed harder. Avery clung to her, his own mouth stubbornly shut, his face jammed against her shoulder, like denial could somehow change the situation unfolding around them. There had been no time to see how far the fall would be, no way to brace for it or to cushion the landing to come. There was only dropping through the air, surrounded by a sticky rainbow of taffy slime, out of control.
For the first time, Zib realized that “adventure” was not always another way of saying “an exciting new experience” but could also be a way of saying “bad things happening very quickly, with no way to make them stop.” She held tight to Avery, who had already known that sometimes adventures could be cruel, who had already known enough to be afraid.
Neither of them could see the cliff they fell past, but if they had, they would have understood the mud a little better, for the stone was banded in pink and blue and purple, stripes of one color sitting atop the next, like something from a storybook. But storybooks didn’t usually try to kill the people who read them, and as Avery and Zib plummeted through the air, they were both quite sure that they were going to die.
At the bottom of the cliff, the mud had formed a sticky, stripy pool, like the runoff from a candy machine. Avery and Zib tumbled down in a cascade of falling mud; they struck the surface together and sank like small, terrified stones into the terrible depths. Without Avery to press the mud from the grass above, the river stopped flowing, and the last of the mud fell after them with a sucking, slurping sound.