Everyone forgot my birthday as our kitchen became mission control, full of ringing phones, loud voices, and panic. My mother refused to leave the phone, positive Cass would call any minute and say it was all a joke, of course she was still going to Yale. Meanwhile my mother's friends from the PTA and Junior League circled through the house making fresh pots of coffee every five minutes, wiping the counters down, and clucking their tongues in packs by the back door.

My father shut himself in his office to call everyone who'd ever known Cass, hanging up each time to cross another name off the long list in front of him. She was eighteen, so technically she couldn't be listed as a runaway. She was more like a soldier gone AWOL, still owing some service and on the lam. They'd already tried Adam's apartment in New York, but the number had been disconnected. Then they called the Lamont Shipper Show, where they kept getting an answering machine encouraging them to leave their experience with this week's topicMy Twin Dresses Like a Slut and I Can't Stand It!so that a staffer could get back to them.

“I can't believe she'd do this,” my mother kept saying. “Yale. She's supposed to be at Yale.” And all the heads around her would nod, or hand her more coffee, or cluck again. I went into Cass's room and sat on her bed, looking around at how neatly she'd left everything. In a stack by the bureau was everything she and my mother had bought on endless Saturday trips to Wal-?Mart for college: pillowcases, a fan, a little plastic basket to hold her shower stuff, hangers, and her new blue comforter, still in its plastic bag. I wondered how long she'd known she wouldn't use any of this stuff when she'd hatched this plan to be with Adam. She'd fooled us all, every one.

She had come home from the beach tanned, gorgeous, and sloppy in love, and proceeded to spend about an hour each night on the phone long-?distance with him, spending every bit of the money she'd made that summer.

“I love you,” she'd whisper to him, and I'd blush; she didn't even care that I was there. She'd be lying across the bed, twirling and un-?twirling the cord around her wrist. “No, I love you more. I do. Adam, I do. Okay. Good night. I love you. What? More than anything. Anything. I swear. Okay. I love you too.”

And when she finally did hang up she'd pull her legs up against her chest, grinning stupidly, and sigh. “You are pathetic,” I told her one night when it was particularly sickening, involving about twenty I love yous and four punkins. “Oh, Caitlin,” she said, sighing again, rolling over on the bed and sitting up to look at me. “Someday this will happen to you.”

“God, I hope not,” I said.

“If I act like that, be sure to put me out of my misery.”

“Oh, really,” she said, raising one eyebrow. Then, before I could react, she lunged forward and grabbed me around the waist, pulling me down onto the bed with her. I tried to wriggle away but she was strong, laughing in my ear as we fought.

“Give,” she said in my ear; she had a lock hold on my waist. “Go on. Say it.”

“Okay, okay,” I said, laughing. “I give.” I could feel her breathing against the back of my neck. “Caitlin, Caitlin,” she said in my ear, one arm still thrown over my shoulder, holding me there. She reached up with her finger and traced the scar over my eyebrow, and I closed my eye, breathing in. Cass always smelled like Ivory soap and fresh air. “You're such a pain in the ass,” she whispered to me. “But I love you anyway.”

“Likewise,” I said. That had been two weeks earlier. She had to have known even then she was leaving.

I walked to her mirror and looked at all the ribbons and pictures she had taped around it: spelling bees, honor roll, shots from the mall photo booth of her friends making faces and laughing, their arms looped around each other.

There were a couple of us, too. One from a Christmas when we were kids, both of us in little red dresses and white tights, holding hands, and one from a summer at the lake where we're sitting at the end of a dock, legs dangling over, in our matching blue polka-?dot bathing suits, eating Popsicles. On the other side of the wall, in my room, I had the same bed, the same bureau set, and the same mirror.

But on my mirror, I had one picture of my best friend, Rina, my third-?place ribbon from horseback riding, and my certificate from the B honor roll. Most people would have been happy with that. But for me, with Cass always blazing the trail ahead, there was nothing to do but pale in comparison.

Okay, so maybe I was jealous, now and then, but I could never have hated Cass. She came to all my competitions, cheering the loudest as I went for the bronze. She was the first one waiting for me when I came off the ice during my only skating competition, after falling on my ass four times in five minutes.

She didn't even say anything, just took off her mittens, gave them to me, and helped me back to the dressing rooms where I cried in private as she unlaced my skates, telling knock-?knock jokes the whole time. To be honest, a part of me had been looking forward to Cass going off to Yale at the end of the summer.

I thought her leaving might actually give me some growing room, a chance to finally strike out on my own. But this changed everything. Id always counted on Cass to lead me. She was out there somewhere, but she'd taken her own route, and for once I couldn't follow. This time, she'd left me to find my own way.

Chapter 2

The next morning when I woke up I realized I hadn't dreamed at all, not even one fleeting image. I took the book Cass gave me out from under my bed, where I'd hidden it, and opened it to the first page.

There was a drawing of a full moon, sprinkled with stars, in the corner. August 18, I wrote at the top of the page. Nothing last night. And you're still gone. I couldn't think of anything else, so I got out of bed, threw on some clothes, and went down the hallway to the kitchen. The door to my parents' room was closed and my father was in his office, on the phone. He had to have talked to a hundred people in the last twenty-?four hours. “I understand that,” he was saying, his voice level, but I could tell he was frustrated. “But eighteen or not, we want her home. She's not the kind of girl who does something like this.” The door to his office was half open, and I could see him standing by the window, running his palm over the small bald patch at the back of his head.

My father, as the Dean of Students at the university, dealt with problems every day. He was the stand-?in parent for thousands of undergraduates, and was quoted each time a fraternity got caught pulling pranks or a beer bash got out of hand.

But this was different. This was about us.