Half an hour later, while LeeAnn was busy helping a customer near the front of the store, I went to the computer and saw that she was still logged in to Facebook. I moved the cursor up to the search box and typed in the name that had been stuck in my mind for the past thirty minutes.

Skye Starling yielded a single result. I clicked on the profile photo and the image expanded. It was her, without a doubt. Her body type appeared to be different from her mother’s—stronger, curvier—but her flaxen hair and angelic face were Libby’s. Underneath her picture was a single line: Lives in Westport, CT.

“Who’s that?” LeeAnn’s voice called from behind, making me jump.

“Oh, um, sorry!” I stammered. “It’s my friend’s daughter. I just started searching for people I knew to see who might be on here. I’m bored.” I shrugged.

“She’s really pretty. Amazing skin.”

I nodded, starting to relax at the realization that, in LeeAnn’s eyes, I hadn’t done anything all that abnormal. “This is the only photo of her, I guess. You seem to have a lot more on your profile.”

“Well, I can’t see her photos ’cause I’m not Facebook friends with her,” LeeAnn explained knowingly. “If you’re not friends with someone, you can usually only see their profile photo and, like, where they live. Not their whole profile. Unless they’re public, but that’s creepy.”

“Oh.” I felt my brow crease in confusion.

“I’m not friending some rando I don’t know. Just make your own Facebook profile and then you can add your friends who have it. Or your friends’ kids or whatever.”

I nodded, still puzzled by the concept, but determined to find a way to see Skye Starling’s full profile.

Navigating Facebook turned out to be much easier than I’d anticipated. That night I stayed up late, long after Burke and the kids had gone to bed, using our clunky Mac to create my account and profile. Only after I was finished did I realize I couldn’t just “friend” Skye. She had no idea who I was. And if I sent her a message and tried to make the connection, Peter might find out I’d contacted his daughter, and it could look suspicious.

But then I remembered the way LeeAnn was always squealing when she received a new friend request, and I suddenly realized why Facebook was so appealing to teenage girls—it was a literal metric affirming how popular you were.

“I have five hundred Facebook friends, Heather!” LeeAnn had gleefully announced one afternoon, marching into the store with a ginormous smile.

“Five hundred friends?” I’d looked at her in disbelief. “I don’t think I know half that many people.”

In truth I probably didn’t know a hundred people. I didn’t have many friends in New Haven. It wasn’t that I hadn’t had the chance—as a parent of three, it would’ve been easy enough to become friendly with the mothers of my children’s playmates. I simply wasn’t interested in getting to know these women, with their bad dye jobs and bargain-shopping addictions and designer-knockoff purses. They only reminded me of all the ways I’d failed in my life, and of everything Libby Fontaine was that I would never be.

So I declined their invitations to join book groups and garden clubs and made peace with my antisocial existence. The one friendship I did sustain was with Mrs. Lucas, our elderly next-door neighbor who lived alone. A lung-cancer survivor, she’d been married three times—most recently to a Yale law professor—and cherished her collection of Hermès scarves; I liked everything about her. I visited Mrs. Lucas once or twice a week; we’d play cards or watch old movies. Sometimes we’d drink wine and she’d tell me stories about her life.

In the shop, LeeAnn had rolled her eyes. “I don’t, like, actually know all five hundred of my Facebook friends. A lot are acquaintances or whatever.”

“You agree to be friends with people you don’t know?”

“Just people who I have other friends in common with. I figure that I basically know them by, like, the transitive property. Or something.” LeeAnn blew a giant bubble with her gum, the saccharine smell of artificial strawberry filling the air.

I’d stared at her, baffled by her generation and silently praying my own daughters turned out nothing like LeeAnn.

But for better or worse, I knew LeeAnn was an accurate representation of something essential: a teenager’s hunger for popularity. The more Facebook friends you had, the cooler you were.

So I created a second Facebook account, a fake profile for a Julia Miller, resident of Norwalk, Connecticut, one town over from Westport. For her profile picture I uploaded a zoomed-out stock photo from Google of a girl jumping into a lake, her features indiscernible. Then I searched Facebook for others living in Norwalk and Westport and sent friend requests to a couple dozen people from the results. I powered off the computer and climbed in bed beside Burke, jittery and sleepless, like a kid on Christmas Eve.

The next morning, the minute Burke and the children were out the door, I rushed to the computer to check Julia Miller’s Facebook account. Eleven people had accepted my friend requests. A rush of adrenaline surged through me.

By late morning four more users had accepted, and I decided that having fifteen Facebook friends from Fairfield County made my profile legitimate enough. It was time to send a request to Skye. I poured a splash of vodka into my orange juice and mustered the courage to click the gray Add Friend button next to her name.

Afterward I sat staring at the screen, waiting for something to happen. When ten minutes passed with no activity, I remembered that it was the middle of a Thursday and Skye was probably at school. She’d be a senior by now, if my calculations were correct. Or would she be a college freshman? Math never was my strong suit.

I showered and dressed for my shift at the Kitchen Kettle. The afternoon dragged; I was practically twitching with the urge to get home and check Facebook. The owner, an older woman named Deb, was in on Thursdays, so even though the store was dead, I couldn’t get away with messing around on the computer. Instead Deb had me doing inventory and refolding dish towels, and by the time eight o’clock rolled around and my shift was over, I felt as if I’d escaped solitary confinement.

Burke had already given the kids dinner by the time I got home, and the four of them were watching football in the den. I logged on to the computer and into Julia Miller’s Facebook account, my hands trembling with anticipation.

I nearly yelped when I saw the notification that Skye Starling had accepted my friend request. Grinning from ear to ear, I joined my family in the den to watch the rest of the game. I’ve always been good at delayed gratification.

I waited until everyone was asleep before sneaking back downstairs to take a deeper dive into Skye’s profile. I didn’t want to be interrupted. Scenes from her life unfolded before me, a collection of images and messages on her wall that revealed her existence. For me, a gold mine. I took my time perusing the seven photo albums she’d uploaded, unable to believe how easy it was to explore the inner workings of her world. Within a half hour I knew that Skye loved Billy Joel, and that her three best friends were girls named Lexy, Isabel, and Andie. Her family owned a house in Palm Beach, and her grandparents still had that stunning estate on Nantucket that Libby used to talk about. I learned Skye was a senior at a private school in Westport, and that she’d gotten into Barnard early decision. One of Skye’s albums was titled “Lib” and consisted only of pictures of her mom. Dozens of people had liked and commented on every photo. Twins; love youuuuu; the most beautiful soul inside and out; miss her so much; angel; watching down on you forever, babe.

I scrolled through the album so many times my eyes started to hurt from staring at the screen. One photo in particular I couldn’t stop going back to—a picture of Libby standing on the porch of the Starlings’ old house in Langs Valley. In it she held baby Skye, a bundle in her arms, while Nate clutched her leg. To the far right of the frame a toddler sat on the porch; he was faced away from the camera with his little knees tucked, his golden curls illuminated in a ribbon of sunlight. Gus. My stomach knotted at the sight of my baby brother, at the crystal-clear memory of that moment. I had taken the picture, and I’d told Gus to shift over so he wouldn’t be in the Starlings’ family photo.