She wished she could take a photo, but then she heard an engine rev behind her. Emma turned and saw Charlotte watching her from the curb, one eyebrow raised. Just leave, Emma silently willed. I’m fine.

The Jeep didn’t budge. Emma scanned the sidewalk, crouched down, and overturned a large rock near to the porch. To her astonishment, a silver key glimmered underneath. She almost burst out laughing. Hiding keys under rocks was something she’d seen on TV; she didn’t think people actually did it.

Emma climbed the porch stairs and stuck the key into the lock. It turned easily. She stepped across the threshold and gave Charlotte another wave. Satisfied, Charlotte pulled away from the curb. The engine snarled, and the red taillights vanished into the night. And then Emma took a deep breath and pushed open the door to the house.

My house, not that I could recall much of it. The creak of the porch swing I used to sit on and read magazines. The smell of the lavender room spray my mom drenched the place with. I could distinctly remember the sound of our doorbell, two high-pitched, tweet-like dings, and that the front door would sometimes stick a bit before opening. But other than that . . .

The foyer was cool and silent. Long shadows dripped down the wall, and the tall wooden grandfather clock ticked in the corner. The floorboards creaked beneath Emma’s feet as she took a tentative step onto the striped carpet runner that led straight to the staircase. She reached out to flip on a nearby light switch, then hesitated and pulled back. She kept expecting alarms to sound, a cage to drop over her head, and people to jump out and shout, “Intruder!”

Grasping the banister, Emma tiptoed up the stairs in the darkness. Maybe Sutton was upstairs. Maybe she just fell asleep, and this was all a big misunderstanding. This night could be salvaged. She could still have the fairy-tale reunion she’d imagined.

A brown wicker hamper stuffed with dirty towels sat just outside a white-tiled bathroom at the top of the landing. Two night-lights glowed near the baseboard, casting yellowish columns of light up the wall. Dog tags jingled from behind a closed door at the end of the hall.

Emma turned and gazed at a bedroom door. Pictures of supermodels on a Parisian catwalk and James Blake and Andy Roddick playing at Wimbledon hung at eye level, and a pink-glitter placard that said SUTTON swung from the knob. Bingo. Emma pushed gently at the door. It gave way easily and soundlessly.

The room was fragrant with notes of mint, lily of the valley, and fabric softener. Moonlight streamed through the window and spilled across a perfectly made four-poster bed. A giraffe-print rug sat to its left, and an egg chair in the corner was strewn with T-shirts, bikini tops, and a few balled-up pairs of sports socks. On the windowsills were candles in big glass jars, blue, green, and brown wine bottles with flowers protruding from their mouths, and a bunch of empty Valrhona French chocolate wrappers. Every available surface was covered with pillows—there were at least ten on the bed, three on the chair, and even a couple of others strewn around on the floor. A long, white-wood desk held a sleeping MacBook Air laptop and a printer. A single card that said SUTTON’S EIGHTEENTH BIRTHDAY BASH! FABULOUSNESS REQUIRED! was propped up next to the mouse. A filing cabinet beneath the desk had a big pink padlock on the handle and a sticker that said THE L GAME. Was that like The L Word?

But there was one crucial thing missing, Emma thought. Sutton.

Of course I was missing. I gazed around the quiet room along with Emma, hoping it might spark a memory—or a clue. Was there a reason the window that faced the backyard was halfway open? Had I deliberately left a copy of Teen Vogue open to an article about Fashion Week in London? I couldn’t remember reading that issue, let alone why I’d stopped at that page. I couldn’t remember any of the items in this room, all the things that used to be mine.

Emma checked her phone again. No new messages. She wanted to look around the house, but what if she bumped into something . . . or someone? She reached for her phone and composed a new text to Sutton’s number: I’M IN YOUR BEDROOM NOW. WHEREVER YOU ARE, TEXT ME BACK TO LET ME KNOW YOU’RE OKAY. I’M WORRIED.

She pressed SEND. A split second later, a muffled ding-dong emanated from across the room, which made Emma jump. She moved in the direction of the sound, a silver clutch bag next to the computer. She unzipped it. Inside was an iPhone in a pink case and a blue Kate Spade wallet. Emma pulled out the phone and gasped. The text she’d just written glowed on the screen.

She immediately began to scroll through the day’s texts. There was the last one Emma had sent. Above that, at 8:20, was a text from Laurel Mercer, Sutton’s sister: THANKS FOR NOTHING, BITCH.

Emma dropped the phone and backed away from the desk, as if it was suddenly covered in toxic mold. I can’t look through her phone, she scolded herself silently. Sutton might walk in any minute and see. That wouldn’t be the greatest way to start off the sisterly relationship.

She picked up her BlackBerry again and sent Sutton a private message on Facebook saying the same thing—maybe Sutton was just downstairs on a different computer and had forgotten her phone? Then she surveyed the rest of the room. Behind the desk was a bulletin board plastered with pictures of Sutton and her friends, the girls Emma had met just hours ago. Some of them looked recent: In a picture of Sutton, Charlotte, Madeline, and Laurel at the monkey house at the Tucson Zoo, Charlotte wore the same blue dress she’d had on at the party tonight. There was one of Sutton, Madeline, Laurel, and a familiar dark-haired boy standing at the edge of a canyon waterfall. Laurel and the guy splashed each other while Sutton and Madeline struck aloof, blasé poses. Other photos looked much older, maybe from junior high. There was a picture of the trio of friends standing over a bowl of cookie dough in someone’s kitchen, trying to shove goopy spoons in one another’s faces. Madeline wore a ballet leotard and was, er, flatter than she was now. Charlotte had braces and rounder cheeks. Emma stared at Sutton; it was her identical face, just four years younger.

Tiptoeing to Sutton’s closet in the corner, Emma wrapped her hand around the knob. Was snooping in Sutton’s closet just as bad as looking through her texts? Deciding it wasn’t, she pulled open the door to reveal a big square room filled with wooden hangers and organized shelves. Sighing wistfully, she reached out and touched all the dresses, blouses, blazers, sweaters, and skirts, pressing some of the soft fabrics to her cheek.

A couple of games were piled in the back of the closet: Clue and Scattergories and Monopoly. On top of that was a box that said JUNIOR BIRDWATCHER’S KIT. It included a bird book and a pair of binoculars. A tag on the front read: TO SUTTON, LOVE DAD. The box looked unopened; Emma figured Sutton hadn’t much liked the gift. She touched a file folder stuffed with what looked like old tests and papers. A spelling quiz from fifth grade had an A-plus on top of it, but a ninth-grade book report on Fahrenheit 451 had earned a C, accompanied by a note in red pen that said Clearly did not read the book. Then she noticed a paper titled “My Family History.” I don’t know my real family history, Sutton had typed. I was adopted when I was a baby. My parents told me when I was a little girl. I’ve never met my birth mother, and I know nothing about her.

Emma felt ashamed for smiling, but she couldn’t help it.

Emma spotted a jewelry case toward the back of the closet; she opened the lid and sifted through Sutton’s chunky bracelets, delicate gold necklaces, and dangling silver earrings. She didn’t see the locket Sutton had worn in the snuff video though. Maybe she was wearing it now?

I looked down at my shimmering body. I didn’t have it on. Perhaps it was with my real body. My dead body. Wherever that was.

In the three-way mirror at the back of Sutton’s closet, Emma blinked at multiple versions of her stupefied reflection. Where are you, Sutton? she implored in her head. Why did you make me come all this way and then not show up?

She exited the closet. When she sat down on Sutton’s bed, exhaustion flattened her like a bullet train. Her head throbbed. Every muscle felt like a wrung-out sponge. She leaned back on the mattress. It was as soft as a cloud, way better than the Kmart blue light specials foster families always stuck her with. She kicked off her wedges and heard them thud to the floor. She might as well wait here for Sutton. Surely she’d show up sooner or later.

Her breathing slowed. Fake news items swirled through her mind. Girl Impersonates Sister at Party. Sister Is Kind of a Flake. Surely tomorrow would be a better day. Twin Sisters Finally Meet, maybe.

Emma turned over on her side and snuggled into the Tide-scented pillow. The shapes and shadows in the big bedroom became blurrier and blurrier.

And with another few breaths, everything faded away for both of us.

Chapter 8

COFFEE, MUFFINS, MISTAKEN IDENTITY . . .

“Sutton. Sutton.”

Emma awoke to someone shaking her shoulders. She was in a bright room. Green-and-white striped curtains fluttered at the window. The ceiling was smooth and unlined. A low bureau and a large LCD-screen TV sat in the place where Clarice’s ratty dresser used to be.

Wait a minute. She wasn’t at Clarice’s anymore. Emma sat up.

“Sutton,” the voice said again. A blond woman hovered over her. There were tiny streaks of gray at her temples and minute lines around her eyes. She wore a blue suit, high heels, and a lot of makeup. The photo of Sutton’s family raising slushy drinks into the air flickered in Emma’s mind. This was Sutton’s mom.

Emma leapt out of bed, staring crazily around the room. “What time is it?” she exclaimed.

“You have exactly ten minutes to get to school.” Mrs. Mercer shoved a dress on a hanger and pair of T-strap heels at her. She paused on Emma for a moment. “I hope you didn’t walk in front of the open window like that.”

Emma looked down at herself. At some point in the night, she’d sleep-stripped off the striped dress she’d worn to the party and now wore only a bra and a pair of boy shorts. She quickly crossed her arms over her chest.

Then she stared at the wedges she’d kicked to the floor last night. They lay in the exact same spot she’d left them. Sutton’s silver clutch and pink-cased iPhone still sat on her desk. Reality snapped into nauseating focus. Sutton didn’t come back last night, Emma realized. She never found me.

“Wait a minute.” Emma grabbed Mrs. Mercer’s arm. This had gone too far. Something was really wrong. “This is a mistake.”

“Of course it’s a mistake.” Mrs. Mercer rushed across the room and threw a pair of Champion mesh shorts, a racer-back tank top, sneakers, and a Wilson tennis racket into a big red tennis bag with the name SUTTON stitched across the side. “Didn’t you set an alarm?” Then she paused and smacked herself lightly on the forehead. “What am I thinking? Of course you didn’t. It’s you.”

I watched my mom as she dropped the tennis bag on the bed and zipped it up tight. Even my own mother couldn’t tell that Emma wasn’t me.

Mrs. Mercer pointed Emma toward the dress she’d laid flat on the bed. When Emma didn’t move, she sighed, yanked the dress from the hanger, and dragged it over Emma’s head.