Symbolism, Imagery, Allegory
What could possibly be so interesting about a pile of giant rocks? That's probably what's going through Gemma's mind when Ty first leads her to the Separates, the natural boulder structure near his house. "That's what I've called them," Ty explains. "They look unlike … kind of … separate from everything else […] They're alone, but they're together in that, at least" (7.28). Alone but together? Gee, that sounds kind of like two people we know.
The fact that the Separates seem totally out of place compared to the rest of the land isn't the only thing that makes them unique. When Ty allows Gemma to go into the structure on her own, she realizes that the Separates aren't at all what they seem from the outside. Behind the rocks is a path that winds through thick vegetation and trees, even leading to a crystal clear spring. "From where I stood, no one would guess at the greenness and life that those rocks contained," Gemma says, "no one would believe the birdsong. Those rocks were secretive and strange. Like you" (30.5).
Under normal circumstances, comparing a bunch of rocks to a person would seem kind of weird, but Gemma's observation that Ty is like the Separates is actually right on. We are tempted to see him as a monster who kidnaps an innocent girl and puts her in danger, but like Gemma, we begin to realize that he's more complicated than that. As we discuss on Ty's page in the "Characters" section, we can't justify what he does—but we can sympathize with him and see that there's a lot more to him than what people are seeing on the front pages of newspapers.
Gemma, on the other hand, has taken the time to walk through the Separates and finds that they, too, aren't what they appear to be. The cave by the pool that "could have been hiding anything. Snakes, crocodiles … bodies" (16.13) turns out to be a source of water that isn't poisoned but rather a source of life. There is a rich grove of greenery that "wasn't like the desert at all" (16.11). Like Ty himself, a landscape that looks rough and frightening actually contains much more. And some of it is even beautiful.