AERIN STARED AT the message on Seneca’s screen. Her throat felt dry. Her fingers tingled. She could practically hear Brett’s voice. Taunting them.

“Okay.” Seneca’s voice was steady, and her shoulders were squared. “So Brett’s either going to be at the party…or close by, watching. Which means we’re definitely going, too.”

“We’re going to face him?” Aerin cried.

Seneca looked at her like she was crazy. “We can’t just stay home! But I’m thinking we’ll just be on the lookout. We need to figure out who he is. Maybe he’s Corey…or maybe he’s someone else. We’ll have to think outside the box.”

“What if we do spot him at the party?” Madison asked. “What’s the plan?”

Kingston, the Doberman, barked loudly from inside the B&B, making Aerin jump. “I think we play it cool,” Maddox whispered. “We don’t know where Chelsea is, and we don’t have any hard evidence we can give the police that Brett has her. That’s what we need tonight. If Brett thinks we haven’t found him, he might get cocky and give away something about where he’s hidden Chelsea…or else bail on the party and lead us straight to her. So we act oblivious. Pretend we don’t see him.”

“Agreed,” Seneca said. “We just track him. Don’t go up to him. Don’t look at him. Pretend nothing’s out of the ordinary.”

Aerin swallowed hard. The idea of keeping a cool head in the face of her sister’s murderer sounded impossible, but if there was any time to rise to the challenge, it had to be today. “What do you think he means by a surprise?” she asked, pointing to that part in Brett’s note.

Seneca shifted from foot to foot, her expression darkening. “I don’t know. But we need to keep in each other’s sight at all times. And we’ll put the cops on speed dial, just in case.” She pulled Madison over and took Aerin’s hand. “Now I need to check out your suitcases.”

“Why?” Aerin asked.

Seneca gave her a half smile. “I didn’t exactly bring clothes for a party. But something tells me you guys did.”

SIX HOURS LATER, after trying on multiple dress-and-shoe combinations and having multiple freak-outs, Aerin and the others stood across the street from the condos in front of a mini-golf course called Zoo Adventure. Even from a half block away, they could hear music floating out from the pool area and a few loud hoots of laughter. Aerin took a deep breath, feeling like she might puke. As they stepped onto the sidewalk, she slipped her hand into Seneca’s. Seneca squeezed back, but it didn’t help much.

The sun had set over the buildings, turning the sky a mix of pink and yellow. Heat still radiated off the sidewalks, but the breeze felt cool and refreshing. At the condo entrance, the music had grown louder, and so had the crowd. A tall, thick-necked man standing at the gate straightened as they approached.

“Name?” he asked, eyeing them coolly.

“Aerin Kelly,” Aerin said in almost a whisper. She looked around, wondering if Brett was close, listening.

The man checked a list on his phone, then nodded and let her through. Seneca, Maddox, and Madison gave their names as well. Aerin watched as Seneca peeked at the bouncer’s phone screen, clearly searching for Corey’s name. But the bouncer gave her a suspicious look and dropped the phone into his pocket.

They walked through the gate and into the huge pool area, where the party was taking place. It held a wide expanse of tables, several long grassy nooks, a bar area, a DJ booth and dance floor, and, of course, the enormous, glittering, open-to-the-sky-and-beach-beyond pool, complete with waterslide, diving boards, a swim-up bar, and a battalion of rafts. A number of kids were in the pool already, and the space smelled like a mix of chlorine and tiki torches. As Aerin scanned the crowded deck, she suddenly had a horrible thought and grabbed Seneca’s hand. “What if Brett brought a gun?” she whispered. “What if that’s his surprise?”

Seneca frowned. “Doubt it.”

“What makes you so sure?”

“Brett strikes me as someone who thinks he’s better than weapons. Like he can outmuscle everyone with his brain.”

They pushed into the party some more. The pool area was decorated with French flags, statues of militiamen on horses, and banners that read, Happy Bastille Day! The food spread seemed to consist mostly of French bread, wheels of Brie, baskets of fries, a huge cauldron of mussels and clams, and a large chocolate cake iced with Let them eat cake! There were at least ten people dressed up as characters from Les Misérables. In the corner, past the waterslide, was a large bounce house; someone had written in black ink on one of the turrets Storm the Bastille! Everyone jumping inside waved cardboard swords and shields.

“Let’s fan out,” Seneca murmured in Aerin’s ear.

Aerin’s heart thumped double time. She didn’t want to be separated from the group even for a second. Seneca added, as if reading her mind, “Just stay where I can see you. It’ll be okay.”

Then Seneca crossed the patio. Madison took a spot near the pool. Maddox headed toward the dance floor. Fearfully, Aerin stepped near a bunch of kids lounging on oversized outdoor beanbags, figuring there was safety in numbers. She glanced around hesitantly, fearful of what she might see. So many people were wearing hats, eye masks, sometimes complete face masks. Was Brett lurking under one of them? She felt eyes on her. She jolted up, but all she saw was a seagull sitting atop the fence.

She moved jerkily, glancing over her shoulder every few seconds, until she was near the bounce house. A song by Demi Lovato played at deafening volume, making it difficult to think straight. The bounce house shook wildly, stuffed with people. Behind it, a couple made out against the wall, their arms and legs entangled. Aerin squinted hard—the guy’s eyes were shaped like Brett’s, and a big beard covered his face like a disguise. He caught her staring, and she noticed a big nose, wide-set eyes. Her Brett radar didn’t flash.

Eyes, faces, bodies. Hats, masks, costumes. She scanned each party guest thoroughly, but the twinkling fairy lights combined with the dark, moonless sky cast confusing, obfuscating shadows. A few of the Les Mis characters were now singing a song from the show, which gave Aerin a pang—Helena always used to love Les Mis, often choosing songs from its sound track to sing in their garage karaoke booth. She’d enjoy this party, actually. She’d probably get up there and sing, too.

Across the patio, Seneca sipped a drink, coolly surveying the pool area. Madison was stationed by the snacks, talking to a girl in a corset. The hair on the back of Aerin’s neck prickled again, and all at once, she felt a watchful presence. She turned slowly, nearly getting mowed down as a knot of laughing, tipsy kids hurried past. A cackle rose through the crowd, high and sharp. A tall head bobbed above the others—someone in a pirate hat. Aerin looked right and left, her thoughts splintering. Then someone pulled her backward.

“Hey!” she cried, staggering in her high wedges. She scanned the area for the others—did they see this? Were they watching? But she couldn’t see Seneca or Maddox anymore, and Madison’s attention was elsewhere. Whoever had grabbed her pushed her into a dark corner and then spun her around to face him. Aerin breathed in, stiff with fear, gaping into a stiff mask of a man with a pageboy haircut and a silky goatee. Her heart lurched. She was about to scream when the masked man’s hand clapped over her mouth.

“Shhh.” His voice was muffled. “Don’t make a scene. I just want to talk to you, Aerin.”

The scream stilled in Aerin’s throat. It wasn’t Brett’s voice…but she knew it all the same. And when he lifted the mask up just so, revealing full lips and a square jaw and those familiar soft green eyes, she was certain.

Thomas.

THE PARTY THRUMMED and shimmered around them. Kids splashed down the waterslide. Someone called, “Limbo!” Aerin was astonished the world could continue so happily apace despite what was happening to her.

Hastily, Thomas loosened his grip, but he still held on to her wrist as though he feared she might bolt. He faced the party again. For a moment, they stood silently side by side, like strangers on a curb waiting for the light to change. “I think I know why you’ve been avoiding me,” he finally murmured. “Brett told you not to tell anyone, right?”

Aerin swallowed hard. Her blood felt like ice in her veins.

“But if you think I’m going to just sit back and watch this happen without helping, you’re crazy.”

“Thomas, you need to go,” Aerin said frantically. “This isn’t safe—for any of us.”

“He’s here, isn’t he? That’s why you’re here.”

Aerin’s jaw twitched. “Have you been spying on me?”

The mask bobbed, and for a moment, Thomas didn’t speak. “No. Okay, maybe. Okay, yes. I’ve been watching you all day, and all yesterday, too. And I overheard Seneca say something about Brett sending her a message earlier. Are you guys communicating with him?”

“Shhh,” Aerin said, feeling uneasy. Come to think of it, she had felt paranoid someone was watching them that morning…but she’d chalked it up to nerves. She glanced over her shoulder, wondering who else could be listening now. Every shifting body, every lurking presence in a mask filled her with paralyzing dread and fear. On instinct, she moved a little closer to Thomas. As complicated as she felt about him being here, she needed protection. All of a sudden, she weakened. How bad would it be if she told Thomas everything? He’d already practically figured out the whole story on his own anyway, and he wasn’t taking no for an answer.

She sighed. “Fine. He’s here. But keep your voice down. He said that if we went to the police, Chelsea would die. You’re ex-police, so…”

“Got it,” Thomas said, his voice full of vindication.

As briefly as she could, Aerin filled Thomas in on some other details—Brett’s letter, the CNC posts, and their suspects thus far. “Brett said he’d be here tonight—with a surprise,” she added. “But I don’t see him yet.”

Thomas peered around the party. To an onlooker, he just seemed like a guy in a mask standing next to a pretty blond girl in a sundress, trying to figure out how to talk to her. Aerin noticed Seneca reappear, look her way, and frown. She could tell Seneca was about to come over, but she waved in an I’m-okay gesture.

The party had swelled in size in the past half hour. A horde of surfers chatted in the corner. A few girls who’d complimented Aerin’s purse earlier that day waved from the beer keg. She noticed Gabriel Wilton, the party host, wearing a large Napoleon-style hat that completely engulfed his head and a heavy-looking blue blazer with gold tassels on the epaulets. He stood next to a guy who wore a towering powdered Marie-Antoinette wig, no shirt, and a French flag wrapped around his waist like a sarong.

“I sort of remember what Brett looked like, but I don’t see anyone like him,” Thomas said.

“He could be in a mask. Or maybe he’s not here yet. Promise me one thing, okay? If we do see him, don’t do anything rash.”

Thomas nodded again. After a beat, he cleared his throat. “So how are you?”

Aerin glared at him. Did he really expect her to answer?

“It’s a party,” Thomas reminded her. “We should act like we’re having a good time.”

Aerin rolled back her shoulders. “I’m fine,” she said begrudgingly. “Great, in fact.”

“Good,” Thomas said. “Me too.”

“Great,” Aerin snapped, though she felt a dip of disappointment. Of course Thomas was happy in his new life.

But then Thomas’s chin tilted down. “Oh, what am I saying? New York is crazy. It’s so crowded, and it smells, and there are people everywhere.”

Aerin bit her lip, suddenly guilty that she’d wished for Thomas’s misery. “But you like school, don’t you?”

“It’s…okay.”

A few new kids had streamed in, whooping loudly. Though some of them were in masks, no one matched Corey’s height or weight, and none of them looked like the old Brett, either. Aerin’s gaze flicked to several kids typing frantically on their phones. They seemed jittery, and they kept looking cautiously around the area. What if Brett had some sort of network, and these guys were warning him that she and the others were here?

“This must be really hard for you,” Thomas said, breaking the silence.

Aerin stiffened. “What?”

“Diving back into this investigation again. It’s like the nightmare that never ends.”

The corner of her mouth twitched. “Yeah. Good times.”

“You should have called me. I’m always here to listen.”

“I’m fine,” Aerin said frostily. She stood on her tiptoes, pretending to be interested in a guy who’d just jumped into the pool.

“I wouldn’t be fine.”

Aerin clamped her lips together. The party felt too crowded and close. Or maybe Thomas felt too crowded and close, his questions too intrusive. Did he really think he could march back in here and take the same old spot in her heart? “Maybe we should mingle,” she said. She shot him a tense smile and began to cross the patio.

Thomas caught her arm. “Aerin. Please. Don’t walk away from me.”

She didn’t turn. “I don’t want to arouse suspicion. We need to circulate.”

“Wait.” Thomas’s muffled voice cracked beneath the mask. Reluctantly, Aerin stopped, her shoulders tense. “Why do you hate me?” he asked. “I’m the same person, and I’m not going anywhere. I promise.”

“Except to New York.” Aerin wanted to take it back as soon as she said it. The hurt was evident in her voice, a chink in her armor.

Thomas went still. The whole party seemed to still, actually—Aerin was suddenly aware of all the space around them. Floating above them was the fragrant, summery smell of grilled burgers and hot dogs. She lingered on the sensation for a moment, letting it fill her. If she shut her eyes, she could almost imagine standing in her own backyard on a summer evening six years ago, before Helena was gone, before her parents split up. Her father was grilling on their three-tier deck. After they ate, she and Helena were going to retreat to the garage, where they’d sing in their karaoke booth for hours. A fresh wave of sadness cascaded over her.

Thomas’s shoulders rounded with hurt. “Y-you’re mad I went to New York?”

The lump in Aerin’s throat grew larger. “It doesn’t matter.”

“But New York isn’t even far. It’s a quick train ride. We could have visited each other every weekend.”

Aerin was clenching her jaw so tightly that it ached. “I said it doesn’t matter. None of it matters.”

“Stop pushing me away. What do you want, Aerin? What can I do to make this better? For you to talk to me again?”

Aerin opened her mouth, but no words came. She stared across the glittering surface of the pool.

“I didn’t even think you cared I went to New York,” Thomas said.

Aerin let out a surprised laugh. “Why?”

The mask didn’t move. Aerin wished she could make out his expression. “Because you didn’t react,” he finally answered. “You just…shut down. I figured I wasn’t that important to you.”

Aerin curled her toes. “It’s not that. But I also wasn’t going to try to talk you out of it. You had no future in Dexby. You needed to get out.”

“But I did have a future in Dexby. You.”

It was unbearably sweet, exactly what she longed for him to say to her, and yet she felt the urge to run. Not just out of this party, either, but out of this town. All of this was just too much. Facing this. Rehashing it. Asking for something she needed. It just wasn’t something she could do.

She was pushing Thomas away—again. He was about the millionth person she’d pushed away since Helena vanished. But what did she gain from it? Okay, it kept her safe and sealed, free from hurt. The flip side of that, though, was her crushing loneliness. Which she suddenly felt so acutely, it was almost an ache.

She let out a shaky breath, wondering if she could, just once, ignore her instincts. “Okay, I didn’t want you to leave,” she said in little more than a whisper, barely audible over the loud techno that was now blasting out of the speakers. “Are you happy now?”

“I…am,” Thomas said immediately. “And…well, I’ve been thinking. I want to come back to Dexby. I miss it there. I miss my grandparents. And I miss…you.”

She gave him a sidelong glance. “Don’t just come back because of me.”

“I wouldn’t be. I’ve looked into colleges right around Dexby, and they have the same programs I was interested in at the New School. But without the crowds in New York…and with you.”

Aerin turned to him. There were so many things she wanted to say—things maybe she could say. Because Thomas would listen. She knew he would. Who else would have followed her all the way to Avignon just because he was worried? Who else would have risked so much to approach her at this party? Who else would wear such a horrible mask to remain incognito?

He cared. Really, really cared—and maybe she could let herself care, too. It was the most incredible feeling of freedom, even amid all this turmoil. Slowly, she inched toward him until their shoulders were touching. Their fingers brushed together. Thomas caught her pinkie and curled it into his palm. Aerin felt a swoop in her stomach and shut her eyes.

All at once, he was pulling her close. At first, she felt the plastic mask against her cheek, but then it gave way, lifting off his face. His breath was warm and sweet, and she could just make out his twinkling eyes. Her heart rocketed as he gently touched the edge of her lips with the tip of his finger. And then, unable to stand it any longer, she pressed her lips to his, savoring the rush and the release of the kiss.