“It can’t be,” Hanna echoed weakly. What was Aria saying?

Aria pushed a stray strand of hair behind her ears. “Jenna said that she came to Ali with the plan to hurt Toby. She wanted him gone—I’m sure because he was…you know. Touching her. Ali said she’d help. Only, things went wrong. But Jenna kept the secret anyway—she said that things worked out the way she wanted. Her brother was gone. But…she also said that someone else was there that night. Besides Ali, and besides us. Someone else saw.”

Emily gaped. “No.”

“Who?” Hanna demanded, feeling her knees go weak.

Aria shook her head. “She wouldn’t tell me.”

A long pause followed. A bass line from a Ciara song throbbed in the background. Hanna looked around the party, amazed at how blissfully unaware everyone was. Mike Montgomery was grinding against some girl from the Quaker school; the adults were all hovering around the bar, getting drunk; and a bunch of girls in her grade were whispering cattily about how pudgy everyone else looked in their dresses. Hanna almost wanted to tell everyone to go home, that the universe had tipped upside down and right now, having fun was out of the question.

“Why did Jenna go to Ali, of all people?” Emily sounded out. “Ali hated her.”

Aria ran her fingers through her hair, which was wet from the rain. “She said that Ali would understand. That Ali had sibling problems, too.”

Hanna frowned, confused. “Sibling problems? You mean like Jason?”

“I…I guess,” Aria mused. “Maybe Jason was doing what Toby did.”

Hanna wrinkled her nose, recalling Ali’s handsome-but-sullen older brother. “Jason was always kind of…weird.”

“You guys, no.” Emily’s hands fell to her lap. “Jason was moody, but he wasn’t a molester. He and Ali always seemed really happy around each other.”

“Toby and Jenna seemed happy around each other, too,” Aria reminded her.

“I heard, like, one in four boys is abusive to his sister,” Hanna seconded.

“That’s ridiculous,” Emily snorted. “Don’t believe everything you hear.”

Hanna froze. She whipped her head around to Emily. “What did you just say?”

Emily’s lip trembled. “I said…don’t believe everything you hear.”

The words fanned out in sonarlike concentric circles. Hanna heard them again and again, banging back and forth inside her head.

The foundations of her brain started to crumble. Don’t believe everything you hear. She had seen those words before. It was her last text. From A. From the night she couldn’t remember.

Hanna must have made some sort of noise because Aria turned. “Hanna…what?”

Memories began to flood back to her, like a line of dominoes falling down one after another. Hanna saw herself wobbling into Mona’s party in the court dress, freaked because it didn’t fit. Mona had laughed in her face and called her a whale. It wasn’t Mona who had sent her that dress, Hanna realized—A had.

She saw herself taking a step back, her ankle buckling, and collapsing to the ground. The devastating riiiippppp of seams. The sounds of laughter above her, Mona’s loudest of all. And then, Hanna saw herself much later, sitting alone in her Toyota Prius in the Hollis Planetarium parking lot, wearing a sweatshirt and gym shorts, her eyes puffy from crying. She heard her BlackBerry chime and she saw herself reaching for her phone. Oops, guess it wasn’t lipo! the text said. Don’t believe everything you hear!—A

Except the text wasn’t from A. It had been from a regular cell phone number—a number Hanna knew well.

Hanna let out a muffled shriek. The faces looking down at her blurred and shimmered, as if they were holograms. “Hanna…what is it?” Emily shrieked.

“Oh. My. God,” Hanna whispered, her head reeling. “It’s…Mona.”

Emily frowned. “What’s Mona?”

Hanna pulled off her mask. The air felt cool and liberating. Her scar pulsed, as if it was a separate entity from her chin. She didn’t even look around to see how many people were staring at her bruised, ugly face, because right now, it didn’t matter. “I remember what I was going to tell you guys that night, when I wanted to meet you at Rosewood Day,” Hanna said, tears brimming in her eyes. “A is Mona.”

Emily and Aria stared at her so blankly that Hanna wondered if they’d even heard her. Finally, Aria said, “Are you sure?”

Hanna nodded.

“But Mona’s with…Spencer,” Emily said slowly.

“I know,” Hanna whispered. She tossed her mask on the couch and stood up. “We have to find her. Now.”

34

I’LL GET YOU, MY PRETTIES…

It had taken Spencer and Mona almost ten minutes to cross the country club lawn to the parking lot, climb into Mona’s enormous taxicab-yellow Hummer, and roar out of the parking lot. Spencer glanced at Hanna’s receding party tent. It was lit up like a birthday cake, and the vibrations from the music were almost visible.

“That was a really awesome thing you did, setting up Justin Timberlake for Hanna,” Spencer murmured.

“Hanna’s my best friend,” Mona answered. “She’s been through a lot. I wanted to make it really special.”

“She used to talk about Justin all the time when we were younger,” Spencer went on, gazing out the window as an old farmhouse, which used to belong to one of the DuPonts but was now a restaurant, flew past. A few people who had finished dinner were standing out on the porch, happily chatting. “I didn’t know she still liked him so much.”

Mona smiled halfway. “I know lots of things about Hanna. Sometimes I think I know Hanna better than Hanna knows herself.” She glanced at Spencer briefly. “You have to do good things for people you care about, you know?”

Spencer nodded faintly, biting at her cuticles. Mona slowed for a stop sign and rooted around in her purse, pulling out a pack of gum. The car immediately smelled like artificial bananas. “Want a piece?” she asked Spencer, unwrapping a stick and pushing it into her mouth. “I’m obsessed with this stuff. Apparently you can only get it in Europe, but this girl in my history class gave me a whole pack.” She chewed thoughtfully. Spencer waved the open pack away. She wasn’t much in a gum-chewing mood right now.

As Mona passed the Fairview Riding Academy, Spencer smacked her thighs hard. “I can’t do this,” she wailed. “We should turn around, Mona. I can’t turn Melissa in.”

Mona glanced at her, then turned into the riding academy’s parking lot. They pulled into the handicapped space and Mona shifted the Hummer into park. “Okay…”

“She’s my sister.” Spencer stared blankly forward. It was pitch-black out, and the air smelled like hay. She heard a whinnying in the distance. “If Melissa did it, shouldn’t I be trying to protect her?”

Mona reached into her clutch and pulled out a Marlboro Light. She offered one to Spencer, but Spencer shook her head. As Mona lit up, Spencer watched the orange butt glow and the smoke curl, first around the Hummer’s cabin, then out the slight crack at the top of the driver’s side window.

“What did Melissa mean in the bathroom?” Mona asked quietly. “She said, after what you told her at the beach, she thought you guys had an understanding. What did you tell her?”

Spencer dug her nails into the heels of her hands. “This memory had come back to me about the night Ali went missing,” she admitted. “Ali and I had this fight…and I shoved her. Her head smacked against the stone wall. But I’d blocked it out for years.” She glanced at Mona, gauging her reaction, but Mona’s face was blank. “I blurted it out to Melissa the other day. I had to tell someone.”

“Whoa,” Mona whispered, glancing at Spencer carefully. “You think you did it?”

Spencer pressed her palms into her forehead. “I was definitely mad at her.”

Mona twisted in her seat, breathing smoke out her nose. “A put that photo of Ali and Ian in your purse, right? What if A fed Melissa some sort of clue, too, convincing her to tell on you? Melissa could be going to the cops right now.”

Spencer’s eyes widened. She remembered what Melissa said about them no longer having an “understanding.” “Shit,” she whispered. “Do you think?”

“I don’t know.” Mona grabbed Spencer’s hand. “I think you’re doing the right thing. But if you want me to turn around and go back to the party, I will.”

Spencer ran her fingers against the rough beads on her clutch. Was it the right thing? She wished she hadn’t been the one to discover Melissa was the killer. She wished someone else could’ve found out instead. Then, she thought about how she’d torn around the country club tent, looking frantically for Melissa. Where had she gone? What was she doing right now?

“You’re right,” she whispered in a dry voice. “This is the right thing.”

Mona nodded, then shifted gears again and backed out of the riding school lot. She tossed her cigarette butt out the window, and Spencer watched it as they drove away, a tiny flicker of light among the dry blades of grass.

When they were farther down the road, Spencer’s Sidekick beeped. Spencer unzipped her bag. “Maybe that’s Wilden,” she murmured. Only, it was a text from Emily.

Hanna remembered. Mona is A! Reply if you get this.

Spencer’s phone slipped from her hands to her lap. She read the text again. And again. The words might as well have been written in Arabic—Spencer couldn’t process them at all. R U sure? she texted back. Yes, Emily wrote. Get out of there. NOW.

Spencer stared at a billboard for Wawa coffee, a stone sign for a housing development, then an enormous, triangular-shaped church. She tried to breathe as steadily as possible, counting from one to one hundred by fives, hoping it would calm her down. Mona was watching the road carefully and dutifully. Her halter dress didn’t quite fit her in the chest. She had a scar on her right shoulder, probably from the chicken pox. It didn’t seem possible that she could have done this.

“So was it Wilden?” Mona chirped.

“Um, no.” Spencer’s voice came out squawky and muffled, like she was talking through a can. “It was…it was my mom.”

Mona nodded slightly, keeping the same speed. Spencer’s phone lit up again. Another text had come in. Then another, then another, then another. Spencer, what’s going on? Spencer, pls txt us back. Spencer, yr in DANGER. Pls tell us if yr okay.

Mona smiled, her canine teeth glowing in the dim light shining off the Hummer’s dashboard console. “You’re certainly popular. What’s going on?”

Spencer tried to laugh. “Um, nothing.”

Mona glanced at Spencer’s main text message window. “Emily, huh? Did Justin show up?”

“Um…” Spencer swallowed audibly, her throat catching.

Mona’s smile evaporated. “Why won’t you tell me what’s going on?”