“Maybe this way,” said Green, “off the edge of the map. We can find a New York map when we cross the border.”

“That’s no good,” said Kira, thinking back to the map she’d had before. “West of here is just more lakes—there are hundreds of them. I don’t know if the Ivies patrol them, but I want to avoid them just in case. Our best bet is south.”

“South to where?” asked Green. “We may as well have this conversation now, if we’re planning our travel. I’m a deserter, so I can’t go near Morgan’s territory, and after the Ivies I’m a little leery of trying to meet up with any of the other factions.”

“I know how you feel,” said Kira. “My plan was to visit as many of the smaller factions as I could, but now . . .” She hoped the others weren’t as violent as the Ivies, and hoped even more that none of them had anything as creepy as a “Blood Man,” but how could she be sure? Should she risk it? If even one more faction captures me for some kind of . . . ritual sacrifice . . . is it worth it?

I’m trying to save the world, she thought. That’s worth anything.

She looked at Green. “I’ve never told you why I came here.”

“I was wondering about that.”

“Dr. Morgan is dangerous,” said Kira. “I assume I don’t have to tell you that, seeing as how you ran away from her.”

Green said nothing, and Kira continued. It was the first time she would propose her plan to anyone, and she was grateful it was just one person instead of a big group. She didn’t know how to present it. She already felt weird about starting with Morgan, and backtracked a bit.

“The humans are dying of RM,” she said, “and the Partials are dying of expiration. What I discovered while studying Morgan’s files is that the cure for one is the same as the cure for the other: Partials produce the cure for RM, and humans in turn are able to produce a particle that inhibits expiration in Partials. Both of the cures were engineered this way. So the only way to save both species is to live together. In peace, preferably.”

Green’s silence betrayed his skepticism. Kira went on.

“I mean we have to coexist, closely. Live in the same area, work together . . . basically just act like we’re one species instead of two.”

“That doesn’t make sense.”

“I’m trying to explain it,” said Kira. “The transmission of the particles would be almost impossible to replicate in a lab, not on the scale we’re talking about—tens of thousands of humans and hundreds of thousands of Partials. The two species can cure each other, but they’d have to be constantly breathing the same air. They’d have to live together without fighting.”