It started when she bumped into a strange man in one of the less-populated areas of the Nexus. She really hadn't been watching where she was going, and she'd ended up on her ass. He'd helped her up, worrying that he'd hurt her... and the two had ended up talking. Her elbow hurt a little, so she let him look at it; it turned out he was a doctor.
Somehow, in only a few sentences, he managed to coax out the fact that she was one of the Nexus's many orphan-runaways. And she learned that he was a psychiatrist who specialized in working with adolescents. Yeah, there was something very fortuitous about their meeting. Soon she was telling him things she hadn't admitted to anyone: her mother's death, hiding out, and the way animals just made sense to her.
Although she still wasn't entirely sure about the offer he'd made her, she took it. If she was so good with animals, he told her, he knew of a place where she could stay. He'd just bought a horse farm. The old owner was staying on to manage the place, but hadn't been able to afford its expenses anymore. He could use some help, especially from someone with an enhanced understanding of animals, and she could board in the big farmhouse. She let Dr. Anders take her there and look around, and talk to the old man. Soon she was sure that neither one of them were the kinds of people who'd prey on a girl her age, and the room they offered her was great. She settled in happily, and then went to meet the horses.
Most of the stalls were empty; the horses were out in the paddock. Nat sat down and had a long talk with several of the barn cats, and then went out and talked to the horses.
Now she was sure. The old man was safe, and the doctor was a cat-petter and knew how to be polite to dogs and horses. Good people, and they were going to watch out for her. Improbably, she'd found herself a home.