"Hello? Is anyone out there?" Halen shouted, paying careful attention not to touch the invisible barrier. She wouldn't repeat her mistake.

As she leaned closer, the hum grew higher in pitch. When she retreated, the hum sang in a low alto tone. With her nose inches from the barrier, the wall squealed, ready to strike. She wasn't getting out that way. Frustrated, she sat back down and pulled another piece of plant from the hole in the mattress.

Silver fins pricked her thoughts. What she witnessed in the ocean wasn't of this world. She ran her hand over her black-stained veins. Had the boy saved her? From mermaids? She shook the ridiculous thought away. He didn't have a scratch or bruise on him. Clearly, she was mistaken.

When she glanced up, the boy with the stormy gaze stared back.

Halen sprang to her feet. She swallowed hard, searching for the courage to speak.

"Are you feeling better?" He stepped forward, a lock of blond hair falling across his forehead.

"I would feel much better if you let me out."

"Promise not to run?" he asked.

She nodded, though she wasn't making any guarantees.

He opened his fist, revealing a smooth oval stone, the perfect kind for skipping on still water. When he inserted the stone into a pocket carved into the wall, a popping sound like water dripping into hot oil filled the air. The sound ceased, and he stepped next to her.

Halen's breath quickened. The barrier was down.

Run, her thoughts urged. But to where? She had no clue where she was.

He reached for her arm, and she inched away. "I won't hurt you."

"You let me get shocked." She reminded him.

"I tried to warn you."

"Not very hard." She balled her hands into fists. "Do you have Tage too? Is she locked away in some cave?"

"Tage?" His brow furrowed. "I thought you were alone?"

"You're a Hunter?" she asked again because he hadn't given her a straight answer before.

"No." His gaze dropped to her bracelet. "Did they come for you?"

"I'm not sure. There was this guy and—" Halen didn't know how to explain what happened. She didn't understand it herself. She rubbed her throbbing head.

"You're lucky the mermaids didn't rip your arm off."

"What?" Her breath hitched. "Are you saying they were real?" Having someone say it out loud somehow made the idea seem more unreal.

"You've never seen one before?"

Memories of her father clawing the water pressed her thoughts. Silver fins curled over his head and crushed him under. Halen's mother diagnosed her wild explanation as trauma-induced delusions. She didn't know what to believe now. "No, I've never seen a mermaid."

"Hmm." He studied Halen as if observing the fine lines of a wasp's wing under a microscope. "You must be pretty freaked out."

"You could say that." She hugged herself.

"Hey, you'll be fine. You might puke a bit more." He nodded to a basin on the other side of the cot. "Once the venom's out, you'll be clear to swim."

Her cheeks flushed. That horrible stench was her? "Clear to swim?"

"Well, you can't stay here."

"Where is here?" She peered around his shoulder. "What is this place?"

"I don't have time to explain. I really need to go." He stepped from the cavern and reached for the rock. "I'll come back for you later."

"No, wait." She darted to his side, her sparks tingling along her arms. "You're not leaving me here."

"It's the safest place." He scanned to his left and then his right. "For both of us."

"Are you hiding?"

He pressed his lips together, his gaze darting into the shadows.

She had drawn this furtive look before. "You are hiding!"

"Maybe I am, but it's none of your business."

"You brought me here." She widened her stance. "If you don't take me with you, I'll scream."

"You wouldn't." He reached again for the rock.

"Try me."

He dropped his hand by his side. "You can come with but stick close." His gaze held warning.

She nodded, relieved he didn't lock her behind the barrier again. But she stopped short after only a few steps. An endless rock tunnel lay ahead; dim light shone from the glowing golden dust ceiling, illuminating several more cells carved within the walls—a person trapped within each. "What the hell is this?" Her breath quickened. "Where are we? Who are these people?"

"It's okay." He tugged her forward. "They're not well. Best not to look at them."

"I don't like this."

"Then stay." He shrugged and started walking.

She glanced back at her rock cell. She wouldn't find her way home just sitting in there. Despite her insides twisting with fear, she followed the boy from her sketchbook.

The ground was compact and cool against her bare feet, the same as the beach on a rainy day. She noticed the boy wasn't wearing shoes either. And she found this strange. But then again, he wasn't wearing much at all. He hadn't changed from the netted shirt and swim shorts since she saw him last. And this confirmed her previous thought—he had to be hiding. But why then bring her along? 

A low drawn-out moan drew her attention to one cell. A bloated man rolled on his mattress. His veins were dark like Halen's, only his feet oozed with green puss. In the next cell, a bone thin woman picked her eyelashes, wishing on each one and sticking them to her tongue. In the last cell, a frail child stared out at the corridor; her black eyes dripped with onyx tears. When they passed, her mouth parted with a howl, and the child ran toward them. Halen stifled a scream, jumping back. But the girl stopped with the high-pitched squeal of the invisible barrier.

"Keep walking," the boy said.

"What's wrong with them?" she asked, but he didn't answer.

When Halen glanced back, the girl slammed her hands to the barrier and was shocked to the ground. "I want to go home—right now." Halen rushed forward.

"Shh. Not so loud." He reeled to face her, and she butted against him. They stood for a moment, locked in each other's gaze; a game she'd played when he was no more than a sketch. But this boy was real. Her heartbeat hammered against her chest with a rushed rhythm, stirring her sparks. Her fingertips warmed and she shook her hands, stepping away.

She felt a tug from behind, pulling at her hair. "Ouch!" She swatted and her finger pricked with sharp pain.

The boy reached around, turning her. "Hold still. You have a flitt in your hair."

"Please get it off. Bugs give me the creeps."

"It likes your hair—they nest in kelp beds." With a sharp tug, he pulled the insect out.

Only when he released it did Halen see it wasn't an insect at all. The tiny creature was only the size of her index finger. Brilliant blue scales coated its arms and legs; its wings transparent like a dragonfly's. The creature had a face like a human, with an upturned nose and beady, black eyes. Its ears pointed sharply, the tip of one coated with Halen's blood.

The flitt, as he had called it, stuck out its long sticky tongue and snagged a strand of Halen's hair.

"Oh no, you don't." He waved the creature off, and it flew up and away until it perched on a spire of long rock springing up from the ground.

The flitt peered down, studying her as if deciding whether to dart for her hair again. But shaking its little head, it took off down the corridor until Halen couldn't see it any longer.

Her attention turned to the vast cavern before her.

Enormous spires jutted from the ground like upside-down icicles. The stalagmites reached up to a dazzling rock ceiling, washed with sparkling dust of tangerine, amethyst, and indigo waves.

"After you." He held out his hand.

Her legs got that gelatin and cream feeling once again, and she stumbled, tripping over a rock and falling to the ground. Her hands sank into a soft cushion of moss. Neon yellow bugs scattered between her fingers, dashing under the moss.

"This isn't real." She glanced around the dazzling cavern, blinking, hoping this impossible place would transform into something she understood. "None of this is real." She twisted her silver bracelet, fighting back the rising tears.

"Come on, you can't stay on the ground." His tone softened.

She shook her head, unable to meet his gaze.

"It will be okay." He took her hand.

Sparks charged up her arm, spreading across her chest, and she gasped.

Over the years, and especially over the last few months, Halen had classified her tingly feelings, like the ones that pestered her to draw the boy before her. Those were harmless, easily tamed with a pencil, unlike the warning sparks that led to burning rooms. But these sparks, tripping along her bones, dancing along her flesh, were a whole new species.

"Please, come with me." He stood, tucking his hand behind his back.

"I'm losing my mind." She shook her head. "I'm insane."

"Maybe you are. I don't know you well enough."

She was about to say how rude he was when she glanced up; a coy smile played on his lips.

A joke. He was joking. Relax. She had to calm down before the wrong kind of sparks ignited. She imagined the rock spires crumbling around them, the ceiling raining rainbow shards. "This isn't a hallucination, is it?"

"You're going to need some time."

He sounded like her mom, asking her to have a good cry. "Why did you bring me here? Where are we?" She fought back the rising sparks.

"You were in rough shape, throwing up and screaming through the fever." He kicked the moss. "A girl I knew died several months ago. Seeing you wounded made me think of her." He looked away. "You're a fighter, though. Few have survived an attack by the mermaids. I shouldn't have let you get near the barrier. I'm sorry."

She didn't know what to make of any of this, but she was alive and he had been the one to save her. "I'm thankful you were in the water. What were you doing there, anyway?" she asked.

"I was on my way here."

"You keep saying here. Where exactly are we?" She scanned the cavern, catching her breath as a fresh wave of sparks spread across her chest.

"Come on. I'll show you."

"Do you have a name?" she asked.

"Dax." He glanced back.

"I'm Halen," she said, even though he didn't ask.

"Well, Halen. We really need to get moving."

She looked up at the boy before her—Dax. Was he her savior, or was this mysterious boy a curse? She didn't know yet. But she knew one thing for certain—he was her ticket home. So she pulled herself together and followed closely as he led her farther into his world.