"Here," Clarke said, handing over the deck of cards she was holding. "It's your deal."

Clarke had been my best friend since we were six years old. There were tons of kids in our neighborhood, but for some reason most of them were in their teens, like my sisters, or four and below, a result of the baby boom a couple of years previously. When Clarke's family moved from Washington, D.C., our moms met at a community-watch meeting. As soon as they realized we were the same age, they put us together, and we'd stayed that way ever since.

Clarke had been born in China, and the Reynoldses had adopted her when she was six months old. We were the same height, but that was about all we had in common. I was blonde-haired and blue-eyed, a typical Greene, while she had the darkest, shiniest hair I'd ever seen and eyes so brown they were almost black. While I was timid and too eager to please, Clarke was more serious, her tone, personality, and appearance all measured and thoughtful. I'd been modeling since before I could even remember, following my sisters before me; Clarke was a total tomboy, the best soccer player on our block, not to mention a whiz at cards, especially gin rummy, at which she'd been beating me all summer.

"Can I have a sip of your drink?" Clarke asked me. Then she sneezed. "It's hot out here."

I nodded, reaching down to get it for her. Clarke had bad allergies year-round, but in summer they hit fever pitch. She was usually either stuffed up, dripping, or blowing from April to October, and no amount of shots or pills seemed to work. I'd long ago grown used to her adenoidal voice, as well as the omnipresent pack of Kleenex in her pocket or hand.

There was an organized hierarchy to the seating at our pool: The lifeguards got the picnic tables near the snack bar, while the moms and little kids stuck by the shallow end and the baby (i.e., pee) pool. Clarke and I preferred the half-shaded area behind the kiddie slides, while the more popular high-school guys—like Chris Pennington, three years older than me and hands-down the most gorgeous guy in our neighborhood and, I thought then, possibly the world—hung out by the high dive. The prime spot was the stretch of chairs between the snack bar and lap lane, which was usually taken by the most popular high-school girls. This was where my oldest sister, Kirsten, was stretched out in a chaise, wearing a hot-pink bikini and fanning herself with a Glamour magazine.

Once I dealt out our cards, I was surprised to see the girl in orange walk over to where Kirsten was sitting, taking the chair next to her. Molly Clayton, Kirsten's best friend, who was on her other side, nudged her, then nodded at the girl. Kirsten looked up and over, then shrugged and lay back down, throwing her arm over her face.

"Annabel?" Clarke had already picked up her cards and was impatient to start beating me. "It's your draw."

"Oh," I said, turning back to face her. "Right."

The next afternoon, the girl was back, this time in a silver bathing suit. When I got there, she was already set up in the same chair my sister had been in the day before, her towel spread out, bottled water beside her, magazine in her lap. Clarke was at a tennis lesson, so I was alone when Kirsten and her friends arrived about an hour later. They came in loud as always, their shoes thwacking down the pavement. When they reached their usual spot and saw the girl sitting there, they slowed, then looked at one another. Molly Clayton looked annoyed, but Kirsten just moved about four chairs down and set up camp as always.

For the next few days, I watched as the new girl kept up her stubborn efforts to infiltrate my sister's group. What began as just taking a chair escalated, by day three, to following them to the snack bar. The next afternoon, she got in the water seconds after they did, staying just about a foot down the wall as they bobbed and talked, splashing one another. By the weekend, she was trailing behind them constantly, a living shadow.

It had to be annoying. I'd seen Molly shoot her a couple of nasty looks, and even Kirsten had asked her to back up, please, when she'd gotten a little too close in the deep end. But the girl didn't seem to care. If anything, she just stepped up her efforts more, as if it didn't matter what they were saying as long as they were talking to her, period.

"So," my mother said one night at dinner, "I heard a new family's moved in to the Daughtrys' house, over on Sycamore."

"The Daughtrys moved?" my father asked.

My mother nodded. "Back in June. To Toledo. Remember?"

My father thought for a second. "Right," he said finally, nodding. "Toledo."

"I also heard," my mom continued, passing the bowl of pasta she was holding to Whitney, who immediately passed it on to me, "that they have a daughter your age, Annabel. I think I saw her the other day when I was over at Margie's."

"Really," I said.

She nodded. "She has dark hair, a bit taller than you. Maybe you've seen her around the neighborhood."

I thought for a second. "I don't know—"

"That's who that is!" Kirsten said suddenly. She put down her fork with a clank. "The stalker from the pool. Oh my God, I knew she had to be way younger than us."

"Hold on." Now my father was paying attention. "There's a stalker at the pool?"

"I hope not," my mother said, in her worried voice.

"She's not a stalker, really," Kirsten said. "She's just this girl who's been hanging around us. It's so creepy. She, like, sits beside us, and follows us around, and doesn't talk, and she's always listening to what we're saying. I've told her to get lost, but she just ignores me. God! I can't believe she's only twelve. That makes it even sicker."

"So dramatic," Whitney muttered, spearing a piece of lettuce with her fork.

She was right, of course. Kirsten was our resident drama queen. Her emotions were always at full throttle, as was her mouth; she never stopped talking, even if she was well aware you weren't listening to her. In contrast, Whitney was the silent type, which meant the few words she uttered always carried that much more meaning.

"Kirsten," my mother said now, "be nice."

"Mom, I've tried that. But if you saw her, you'd understand. It's strange."

My mother took a sip of her wine. "Moving to a new place is difficult, you know. Maybe she doesn't know how to make friends—"

"She obviously doesn't," Kirsten told her.

"—which means that it might be your job to meet her halfway," my mother finished.

"She's twelve," Kirsten said, as if this was on par with being diseased, or on fire.

"So is your sister," my father pointed out.

Kirsten picked up her fork and pointed it at him. "Exactly," she said.

Beside me, Whitney snorted. But my mom, of course, was already turning her attention on me. "Well, Annabel," she said, "maybe you could make an effort, if you do see her. To say hello or something."

I didn't tell my mother I'd already met this new girl, mostly because she would have been horrified she'd been so rude to me. Not that this would have changed her expectations for my behavior. My mother was famously polite, and expected the same of us, regardless of the circumstances. Our whole lives were supposed to be the high road. "Okay," I said. "Maybe I will."

"Good girl," she said. And that, I hoped, was that.

The next afternoon, though, when Clarke and I got to the pool, Kirsten was already there, lying out with Molly on one side and the new girl on the other. I tried to ignore this as we got settled in our spot, but eventually I glanced over to see Kirsten watching me. When she got up a moment later, shooting me a look, then headed toward the snack bar, the new girl immediately following her, I knew what I had to do.