Tally gets pulled into the flying machine (with her hoverboard) and the masked people turn out to be pretties, just like Peris and the others back home. Except these pretties like to set fires. (That's what makes them "firebugs" since that's one way to say "pyromaniac" or "arsonist." But who doesn't like fire, really? Again: do no try at home.)
These pretties are rangers, and they're setting fires to the white flowers because the white flowers are an invasive species that kills off all the other plants.
(And they fly helicopters because helicopters can go anywhere, not like hovercars or hoverboards, which require metals.)
These white tiger orchids used to be rare, but some Rusty changed them so that they're really good at growing. Which isn't so good for everything, including the orchids.
As one ranger explains, the orchids kills off the trees where hummingbirds live and the orchids need the hummingbirds. So the rangers have to keep setting fires to keep the orchids from spreading—and they've been fighting the orchids for 300 years.
These rangers are sometimes friendly with the Smoke runaways and will take Tally to the next meeting place.
So Tally has to start lying to the rangers about how great the runaways are, living in the woods, making the best guacamole, etc.
The rangers drop Tally off among the orchids and leave.
Tally follows the last of Shay's instructions, "Then wait on the bald head until it's light" (84). And luckily, there's a tall hill with nothing on it.
So she waits for something to happen and thinks about how she'll have to betray Shay if she wants to get home.