I couldn’t close my eyes as I lay in bed that night. My foot wouldn’t stop moving, like I was tapping my toe on my blankets.

How many days ago had Lysi made the rock tower? Was it only yesterday? Was she waiting for me now? What if this was the day she had given up waiting for me? She could be on the beach this second, knocking down the rocks. I might never see her again, and she’d swim away thinking I didn’t care whether or not she was alive. She wouldn’t know how sorry I was for what Papa did.

I sat up. Then I thought of Papa in the next room, sure to waken at the slightest sound.

So I flopped back down and rolled on my side.

What, then? Would I let Mama and Papa ruin my friendship with Lysi? Would I just accept never seeing her again? If I didn’t go out to see her tonight, I would be as good as giving up. This would be the first day of the rest of my life: a life without Lysi.

I sat up again. That was not an option. We were supposed to be friends forever. I couldn’t abandon the chance to fix everything Papa had broken. The thought was unbearable.

What about Mama? I couldn’t disappoint her again—but would I be disappointing her if she never found out?

I slipped out of bed before I could change my mind. I would get a flashlight and my coat, and I’d be back before anyone knew I left.

My door opened without a squeak. I dropped to my stomach and slithered under the beaded curtains, careful not to touch them.

Mama and Papa slept with their door open, so I made sure to move on tiptoe, keeping close to the wall where the floor didn’t creak so loudly.

Papa must have had a flashlight somewhere—but I refused to go back into the shed. There had to be one inside the house.

I crept to the rolltop desk in the corner of the living room. It was littered with stray items: measuring tape, stapler, lighter, playing cards, broken pencils.

The drawer was tough to open. I pulled hard, realising it was a stupid idea when it clattered off its slides. I let go and dove to the floor behind the desk.

I clapped my hands over my mouth, listening, but the only sound that followed was the ticking clock on the wall. Mama and Papa hadn’t stirred.

Still, I waited, crouched on the floor and listening. After what felt like forever, I stood and gripped the drawer handle again, gently this time. It stayed jammed. I struggled with it only briefly before deciding it wasn’t worth risking the noise.

Defeated, I glanced around for another option. My eyes landed on a cast iron lantern by the fireplace. A candle was inside, still waxy enough to get me to the beach and back. I pocketed the lighter on the desk.

Lantern in hand, I tiptoed to the front entrance to get my coat, then back to my bedroom where I could slip out the window.

Not so much as a snore came from Mama and Papa’s room at the end of the hall, and I didn’t know if that meant they were quietly asleep, or awake and listening.

I slithered back under my beaded curtains, the lantern cradled inside my jacket so it wouldn’t scrape the floor, and softly shut the door.

My window opened soundlessly. I tossed the lantern into the soggy leaves, where it hit the ground with a clang. Then I hoisted myself over the ledge.

Summer might have been coming, but the temperature on Eriana Kwai was steadily cool year-round. I was glad I had my jacket. I zipped it up to my chin as I crept around the side of the house opposite Mama and Papa’s bedroom window. Only once I reached the road did I light the lantern.

The walk felt longer than usual. The only sounds were a faint buzz of insects, the occasional hoot of an owl, and my bare feet patting against the hard dirt. I couldn’t help feeling like the animals of the night were watching me as I followed the empty road. I stayed in the middle, somehow feeling safer there—like the animals were less likely to jump out at me if I walked far enough away from the forest’s edge.

Eventually, I reached the point when I could no longer avoid going into the woods, and stopped. I glanced into the misty darkness on either side of me. After a moment’s hesitation, I took a breath, switched hands on the lantern to give my left arm a rest, and stepped inside.

The blackness overwhelmed me, even with the glow of the lantern. I hastened forwards, stumbling over tree roots. My coat kept snagging on long-fingered branches. I didn’t care; I was just glad to be wearing it. Already, my teeth chattered—although I didn’t know if that was from the cold.

The whispering surf grew louder with every step, and knowing it was close kept me pushing forwards. By the time I emerged on the rocky beach, I trembled all over, and the skeletal sight of the overturned fishing boat tipped me over the edge of panic.

“Lysi?”

It was too soon for her to hear—she would be at the shoreline, not up in the dry rocks—but I needed to hear a voice, even if it was my own.

Only sloshing waves met my ears.

I gave the fishing boat a wide berth, trying to ignore its ghostly presence. Its black shadow and spider-web fishing nets made the beach seem haunted.

“Lysi, are you here?”

Something sat by the water, perched on a rock. I stopped and held the lantern higher to make sure I wasn’t imagining it. The figure sat gracefully upright and statuesque. I wondered whether it really was Lysi and not just a curvy piece of driftwood, but then the end of a tail flipped up, and she lifted a hand and beckoned me over.

My face broke into a grin. I ran towards her, jumping carefully through the rocks, the lantern clanging loudly.

“I didn’t know if you’d be here,” I said, breathless. “I only saw your rock tower a few hours ago.”

I held the lantern between our faces so Lysi and I could see each other properly.

Only I didn’t see Lysi. I saw a stranger—maybe in her mid-twenties, beautiful and porcelain, with waist-length black hair and a long, slender tail.

“Hello, Meela,” she said, and her pointed teeth glinted in the lantern’s light.

I knew from her eyes that she wasn’t smiling at me—she was baring her teeth.

“I feared we’d waited too long,” she said in a rolling accent, thicker than Lysi’s. “But Lysithea was right. You would still return.”

I stepped back, feeling like my stomach was pushing its way up my throat.

I’d never seen another mermaid except Lysi. Lysi was just a girl, like me—a friend, one who had a tail instead of legs. But something about this mermaid was so inhuman, like she was too perfect, each of her features exaggerated beyond real beauty. Something sinister lived beneath her porcelain flesh.

“I should give Lysi credit for doing a convincing job,” she said. “Or maybe you’re just naïve enough to believe a human and a mermaid could actually be friends.”

What did she mean, Lysi doing a convincing job? My mind worked in slow motion. I was too seized by fear at the sight of this mermaid to form words.

Her upper lip curled, and her eyes changed. A familiar shade of red seeped through them like they were filling with blood, hiding her pupils and any fleck of white.

Something instinctive exploded inside me, yelling at me to run away and preserve my life. This mermaid was about to kill me. She was about to eat me.

“I’m so happy I finally get to see you in the flesh,” she said, reminding me of a purring cat. Her lips retracted from the row of pointed teeth. “Lysithea might not have been strong enough to take you . . . but she said you were easy to fool.”

I screamed, abandoning any attempt at staying unnoticed. Blindingly fast, the mermaid’s hand shot out and seized my ankle. Her long fingers were colder than ice. I tried to step back but her grip was like stone, and I fell hard on my side. My hand shot out to brace my fall and skidded painfully off a rock. The lantern crashed to the ground and the flame died.

The darkness spun, dizzying me as I rolled onto my stomach. A musical sound met my ears, rolling like laughter. Lysi’s laughter.

I scrambled across the rocks, kicking as hard as I could, but she still held my ankle.

“How should we do this?” said the mermaid, her tone suggesting we were about to play a game. “Would you rather be drowned, or strangled?”

She slid off her boulder behind me. My foot made contact with her face, but it was like kicking a tree trunk. She grabbed for my other ankle and caught the leg of my pants.

“Maybe suffocating isn’t your style,” she said. “I don’t mind. You’ll taste better if your heart is still beating.”

She pulled me towards her. I screamed too much to speak. The mermaid’s strength was impossible, even stronger than Papa had been when he hauled me away from Lysi.

My body bumped across the slimy rocks; any stones I tried to grip came loose, but I turned and hurled them at her head. They bounced off her with a dull crack. Her hands stayed clamped on my legs. She didn’t even flinch—I might as well have been throwing sponges.

“You don’t need to draw this out,” she said, her voice now rough and angry.

One of my flailing hands brushed the lantern; I stuffed my fingers through the sides and swung it around with all the strength I had. It smashed into her cheek with another dull crack.

This time, she screamed.

She released my ankles, hands flying to her face where the lantern had struck. I kicked away and crawled over the rocks, ignoring the pain of my knees against the stones.

Her voice exploded with fury. “What is that?”

A hand closed around my ankle again. I screeched and whirled around, striking another blow with the lantern.

She screamed again and fell back.

I gaped at the lantern. Why did this work, but not the rocks?

An odd sizzling sound met my ears, like meat on a grill.

I raised my eyes to the mermaid, unblinking. The sound was coming from her.

Was it the fire from the lantern? I looked down. No, the flame had been extinguished.

The mermaid coughed, as though choking on something. Her red eyes glistened as she locked me into her gaze. She hesitated.

Suddenly I remembered Papa’s weapons hanging in the shed, how the bolts and crossbow had felt in my hands. Cold, black iron.

I stared at the lantern clutched in my fists. Of course—iron!

Without a second thought, I lunged at the mermaid and pushed the lantern hard against her skin. She screamed even louder. Her sharp teeth glinted in the moonlight.

Her hands found their way around my neck. “Get off me!”

But it was working. The sizzling grew louder, and I fought against the urge to let go of my weapon and try to pry her hands away from my throat. I couldn’t breathe—my face felt ready to pop—but I kept the lantern pushed against her skin.

I could see her face blister and darken. The iron burned her wherever it touched. My head felt light, like I was going to lose consciousness. Her strength was overwhelming. I wondered whether she was going to squeeze my head right off.

I told myself to keep pressing the iron against her face, but the feeling in my hands grew distant. My mouth opened and closed like a dying fish. But I still heard the sizzling sound her flesh made. I couldn’t see anymore. Her face must have been blistered, searing . . .

With a cry that echoed through the trees behind us, the mermaid let go of my throat and threw me backwards. All at once, I gasped for breath, hit the rocks with a crack at the back of my skull, and fumbled for a grip on the lantern as my hands bashed against a sharp stone. My vision clouded with spots. I must have been on the threshold of passing out.

My stomach churned as the smell hit my nose, like a mixture of smoke and seaweed and rotting fish. I gave a great, choking sob. My throat still felt like it was being crushed in her stony hands.

Abruptly, the mermaid’s shrieking stopped. I sat up, still gasping and dizzy, and swung the lantern in front of me.

She vanished. I couldn’t see anything, but in the ringing silence, I assumed she’d jumped back in the water.

I stumbled to my feet and sprinted back to the trees. I dropped the lantern in the woods, the muscles in my fingers unable to hold on anymore.

I didn’t stop running, even when I tripped over roots and my breath came out in wheezes and my lungs begged me to stop. I kept running as fast as I could, all the way through the trees and down the dead-end dirt road.

When I reached my yard, I only slowed a little to pull my jacket over my nose and mouth, hoping it would muffle my gasping.

My limbs trembled violently but, somehow, I managed to climb back through my window. I peeled off all my clothes and stuffed them into the gap between my bed and the wall so I could deal with them in the morning. Naked, I jumped under my quilt and pulled it over my head, sealing myself in its cocoon.

For a moment, I stared into the total blackness. And then I started sobbing. I couldn’t stop myself. Pain filled me, from the top of my head to the soles of my feet, and my throat hurt so badly, I kept gagging, even though those icy fingers had long since released me.

Lysi had set me up. That mermaid was supposed to finish me off. The thought was more agonizing than the physical pain throbbing all over my body. Like a needle run through my ribs and into my heart, it brought more pain than anything Mama or Papa had told me about mermaids.

She said you were easy to fool.

Mama and Papa were right. Lysi was supposed to kill me in the end. She’d only been my friend so she could lure me in.

It made sense, when I finally accepted it. Her instincts weren’t to befriend me—they were to trick my emotions so I’d go with her into the water. That was what sea demons did.

I eased over beneath my blankets, sweating and shivering. Though my eyes were shut tight and the quilt enclosed over my head like a den, I knew the sun would be rising soon. Somewhere very, very far away, a bird chirped joyfully.

I considered that Lysi perhaps didn’t know about the other mermaid waiting there. But that didn’t make sense. What about the rock tower? The mermaid wouldn’t have known to set it up, and she wouldn’t have known when and where to wait unless Lysi had told her everything.

Besides, that mermaid had spoken in perfect Eriana. Lysi did teach it to others, after all. Did the mermaids use it to lure sailors? Our sailors?

She said you were easy to fool.

I shuddered convulsively and curled my knees even tighter to my chest. My tear ducts felt dry, eyes swollen shut.

The mermaid’s words were ingrained in me, and I would never forget them. I could never forget the words of Lysi’s betrayal.