“And what will you teach me?” asked Param.

“How to do it backward,” said Noxon. “Because that’s the direction I need to move, too.”

Param shook her head. “I skip time, I don’t change directions.”

“That’s my point,” said Noxon. “What if, when you disappeared, you could slice your way backward in time? When Umbo and I . . . and Rigg . . . when we jump in time, we skip over everything in between. I . . . and Rigg . . . we can see the paths, and the facemask lets us see them as people in motion. Extending backward in time. But they’re always moving forward. So when I attach to them, I attach in the direction they’re going. I need to know how to go upstream. How to slide backward in small increments, and you need to learn the same. I’m hoping we can help each other.”

Param shook her head again. “I can’t do anything like that.”

“We know you can’t,” said Rigg. “That’s what ‘learning’ means. Now you can’t; with work, maybe someday you can.”

“And what will you be doing while Noxon and Param are working on doing new impossible things?” Olivenko asked Rigg.

“I’m planning to go through the other wallfolds, one at a time, and see what they have. We’ve seen Ramfold, Vadeshfold, Odinfold, and Larfold. Fifteen to go.”

“And then what?” asked Olivenko.

“Then I’ll have some kind of idea about what will happen if we bring down the Wall.”

Loaf chuckled. “I can imagine General Citizen and the Sessamoto army trying to make war against the mice of Odinfold.”

“I can also imagine Ramfolders spreading into Vadeshfold and having an infestation of facemasks,” said Olivenko. “Not the fancy versions you and the Riggs have. The original, devastating, bestial ones.”

“That’s an argument right there in favor of never bringing down the Wall around Vadeshfold,” said Param.

“Not that we don’t find the three of you lovely as wild­flowers,” said Umbo.

“I’m a lot prettier than Rigg and Noxon,” said Loaf. “My facemask has had time to grow to fit my original face.”

“That doesn’t always lead toward prettiness,” said Olivenko with a smile that showed he was merely putting Loaf’s own irony into open words.

“So you’re appointed to judge all the wallfolds?” Umbo asked Rigg.

“I’m not judging anything,” said Rigg. “I’m going to go and find out and then we can talk again.”

“And by ‘we’ you mean you and Noxon?” asked Umbo.

“Here we go again,” murmured Param.

“I mean me and you and Loaf and Olivenko and Param, with plenty of advice from the expendables and the ships’ computers,” said Rigg. “Though you don’t have to come to the meeting.”

“And what’s your plan for me?” asked Umbo.