“Because in the future we won’t inadvertently change the past any more than we already have by leaving that note and the knife.”

“But now you don’t have a knife,” she said.

“If we’re lucky, we’ll cease to exist as soon as he finds the knife.”

For the moment, though, he jumped them back in time to an innocuous era, an empty stretch of forest with no recent paths in it. It might be centuries ago, for all she knew.

“Why can’t we stay here?” she asked. “If no one visits here.”

“Because we didn’t.”

“But if we don’t change anything . . .”

“Even sophisticated know-it-alls like us need more human company than each other to survive. As leftovers, as extras, we need to go to a time where we can live without changing history.”

“Rigg, I don’t want to die.”

“The human dilemma. None of us wants to die, but all of us have to do it.”

“What about another wallfold?” she asked.

“All occupied.”

“Vadeshfold?”

“Square is going to put a colony there. It belongs to them.”

“You have a facemask. I’ll get one, too.”

“No,” said Rigg. “And you know why.”

Param couldn’t help it. She started to cry.

“Param, we always knew that what mattered was the survival of the human race on Garden. Not our individual lives.”

“Well, we’ve either saved the human race or failed again, but what about us? Our mission’s over, and here we still are.”

“Once we get past the Destruction,” said Rigg, “the Destroyers will hunt us down and then our troubles are over.”

“And those other Riggs?”

“I think they put up a good fight but the ten aliens who were converging on them killed them all.”

“Couldn’t they have kept duplicating till they outnumbered them all?”

“Could have,” said Rigg, “but to what end?”

“To stay alive!”

“I was staying alive long enough to get information about what that creature was. Its biology. How it could be killed. How its weapons worked. What was inside that aircraft. And to keep it from killing you. And to live long enough to pass all of that on to Umbo and stop us, the real us, the earlier us, from getting trapped in that pit.”

“What will they do? The earlier us, when they get the warning?”

“Well, you’re the Queen-in-the-Tent,” said Rigg. “What would you order?”

“I’d ask for advice.”

“Nobody has any,” said Rigg.

Param thought for a moment. “Just get away?”

“Not a bad plan,” said Rigg. “But that leaves Mother and Haddamander to proclaim that we refused their surrender.”

“Bring an army and trap them in their own firepit,” said Param.

“More satisfying, but then we’re the ones who betrayed and assassinated them.”

“What, then!” Param demanded.

“As I said, I have no idea. No advice. So . . . aren’t you glad that you and I don’t have any such decision to make?”