Ahmad turned to look at her. “Maybe—” he started, and then added, “Oh no.” The earth was practically shivering beneath them, and this time, there was nowhere to move to.

In the distance, the large metal sphere bore down on them.

“Oh my gosh!” Winnie shrieked. “What do we do?”

Before Ahmad could reply, the sphere ricocheted off one of the walls in its path. There was a slow creak, like a deadbolt lock sliding out of its socket, and then . . . all the walls shifted.

“What is happening?” Winnie gasped, as the world collapsed around them, locking them into place.

Ahmad’s eyes lit up as one of the last walls shuddered to a stop.

“That’s it! You know those cheap little maze games they put in holiday goodie bags? There’s a game like that I like to play online, only if the marble touches a certain wall, the entire thing changes.”

“Great. Just great,” Winnie huffed. “And now there’s a wall there.”

There was nothing else for them to do but slap the walls, trying to find another spot that would shift it back. It didn’t help that just beyond the new wall blocking their path, they could see a small pool formed by newly crushed tiles—and the fish they sought happily bouncing up and down in the middle of it.

“It’s laughing at us,” Ahmad said sourly.

Winnie slapped her palm hard on one of the walls closest to her. It shifted, and she turned to Ahmad with wide eyes.

“It worked!”

Unfortunately, that wasn’t the only sound that met the kids’ ears. Ahmad turned to Winnie. There was a creaky roar growing ever closer.

“That huge marble thing is coming back. Hurry, hurry, hurry!”

“This is moving so slow!” Winnie glanced over her shoulder. “Wait, is the sound coming from behind us or in front of us?”

Ahmad tried to put some of his weight on the wall. It still slid slowly, just parting so they could see the glorious blue of the pond waiting for them.

“I can’t tell, but we need to move fast.”

“If it can just move a little . . .”

Winnie waited and then, as the wall slid back, squeezed through the small opening.

“I’m in!” she called. “You next!” She grasped for his hands.

“Don’t wait for me,” Ahmad insisted, waving his hand as he stuck his leg through. “Run for the fish! We don’t know when the maze is going to—”

The kids’ eyes met with dread as a sound rolled down the corridor toward them: a low, dull rumbling.

“Move, move, move!” Ahmad yelled.

Winnie sprinted for the pond while he sucked in his cheeks and tried to slip through. The wall was still shifting frustratingly slowly. There was just enough space, though, if he could only . . .

There was a heavy thud, and then the rumbling stopped.