"Who are you?" the mermaid and I said in unison.

She swam toward me. "How did you get here?" she said. "No one comes here - ever."

"I - I - I swam," I stammered. "Where am I, anyway? And who are you?"

The mermaid swam closer to me, looked me straight in the eyes, swam all around me, then came back to face me. Her face was lined and pale. She seemed old, but at the same time almost ageless, and strangely beautiful. Her silvery hair was so long it flowed all the way down her back and stroked her tail as she swam. Her tail was a musty, dusty mix of mauve and pink. She looked a bit like someone who'd just been presented with a fairly rare, and not particularly pleasant, geological finding.

She didn't answer my question. "Come with me," she said, tugging at my arm.

I pulled away from her. "Not till you tell me who you are," I said. I hoped I sounded braver than I felt.

In reply, she gripped my arm more tightly and pulled me along behind her.

We swam down tunnels, around tubes of weeds, through high-sided channels, under rocks, and around corners until we came to a large sandy opening with an enormous pillar in the middle and caves and arches dug into the walls all around it.

Four mermaids were in the clearing. One was brushing her hair with a makeshift brush that looked as if it were made of twigs. Another had grabbed a pa.s.sing shiny flat fish as it floated by and was peering into its skin to see her reflection. The other two were sitting on the sandy seabed; one looked as though she were making something out of reeds, the other seemed to be playing a game with stones in the sand.

"I found something," the mermaid called out to the others. They all looked up - each face an identical mixture of shock and disbelief. A minute later, they had crowded around me, looking into my face, examining my tail, reaching out to touch me.

"Is she real?" one of them asked.

"Of course I'm real!" I snapped, and she jumped away.

"How did she get in here?" another one asked.

"I can talk, you know," I said. "Why don't you talk to me instead of about me?"

The mermaid who had been making something with the reeds pushed in front of the others, glaring at me so intently that I wished for once in my life I could have kept my mouth shut.

"Leave her be, Nerin," she said. "She is a visitor. Is that not enough? And look - the child is scared. Give her some room."

Her voice was soft and gentle. She seemed younger than the others, although as I looked more closely into her face, I could see that like the rest, she had tiny squiggly wrinkles across her forehead and little claw-shaped lines fanning out beside each eye. Her hair was silver too, but shorter than the first mermaid's.

The others nodded their agreement. "Morvena's right," one of them said, smiling at me. Her smile felt like warm honey flowing over me. I felt my fear and anger melt away. "We should be grateful," she went on. "We should be welcoming her with open arms."

Nerin, the one who'd brought me in, finally let go of me. She brushed my arm where she'd been clutching it. "Of course," she said gently. "I'm sorry. I was just so surprised. You see, we don't get visitors here. Never! Not in all the years we've -"

One of the other mermaids nudged her. "Rarely," she corrected her. "Let's not say never. You'll give the girl a bad impression." She reached out and stroked my hair. "And look at the little jewel that's been washed in now. Girls, let's say thank you. This may be our salvation."

"You're right, Merissa," Nerin said. She swam around me. "A pretty little siren like this," she murmured.

"I'm - um, I'm not exactly a siren," I said nervously.

The mermaid who had been brushing her hair pushed in front of the others and put a spindly arm around me. "Of course you are, dear," she said. "You mustn't say things like that. Putting yourself down is a terrible thing to do - especially in one so young and so pretty." She tilted my chin up. "You listen to your auntie Lorelei," she said softly. "You are a beautiful young siren. Right?"

"Right, OK," I said. At that point, I would probably have agreed to anything she said. They were all being so nice! And there was something about them that was so - what was it? Comforting. Peaceful. It made me feel happy, and I wanted to stay here forever. In that moment, I forgot about everything else. All I could think about was being here, with these mermaids, and feeling this warm, peaceful feeling.

"Now, how about a little song?" Lorelei suggested in that same sweet tone of voice, her smile still big and warm and welcoming. The other mermaids froze and looked first at her, then at me.

"A song?" I said, laughing nervously. "What do you mean?"

The other mermaids were around me in a moment, all with the same encouraging smiles on their faces. Lorelei's arm was still around my shoulders. "A song," she repeated, a slight edge creeping into her voice. "A beautiful siren song, to welcome you here. We'll join in." Her arm still rested lightly on my shoulder.

"You start," Merissa said sweetly.

I burst out laughing. "You clearly haven't heard me sing!" I said.

The arm around my shoulder tightened.

"Whatever do you mean?" Lorelei asked, still smiling, although there was definitely something more strained about the smile now. It was beginning to look as though it had been painted on her face, rather than belonging there naturally.

"I - I mean, well, I can't really sing," I said. "In fact, my singing voice is terrible."

The mermaids stared at me, their expressions suddenly dark and full of threat. They seemed closer than they'd been, right up against me, and their faces looked ugly, their smiles false and harsh.

"Terrible?" one of them said. Then she forced a laugh. "You're being modest."

I laughed back - only my laugh was more of a nervous cackle. "I'm really not," I said. "Even my mom makes me stop, and her voice is bad enough!"

The arm around my shoulder became a vice. Lorelei's fingers dug into my shoulder. "What - do - you - mean?" she whispered hoa.r.s.ely.

"Oww!" I tried to break free from her grip. My shoulder felt as though a scorpion was biting into it. "I mean I can't sing!" I said. "I'm not a siren and I can't sing. If you want beautiful singing, then you need to ask Shona!"

Shona. My chest leaped at the thought of her. Where was she now? How long had I been in here? Was she still waiting for me?

One of the mermaids pushed past Lorelei, picking her hand off my shoulder. She gently took hold of my arm and swam us away from the others.

"h.e.l.lo, dearie," she said. "I'm Amara. Now then. Tell me about Shona," she said softly. "She's a friend of yours, is she?"

I nodded. "My best friend," I said, gulping back a rock-shaped tear in my throat.

"And this Shona," she went on. "She's a good singer?"

"She's the best in her school!" I said proudly.

Amara smiled. "And where do we find her?"

"You tell me!" I cried. "We came out here together. We were looking for -" I stopped, and looked around at the mermaids, all staring intently at me. I'd been right earlier. A mysterious place, hidden in the deeps of the ocean, miles from anywhere. I swallowed down a mixture of fear and excitement. "I think we were looking for you," I said.

Nerin, the first mermaid, joined Amara and me. "Never mind that," she said. "Tell us more about Shona." I could tell she was trying to sound all friendly and nice, but her voice came out desperate and rasping. "Where is she? Where can we find her?"

"I don't know! I've told you. We came here together. We were looking for -" I felt my cheeks heat up and I stopped.

Nerin nudged me. "Go on."

"We were looking for the lost sirens," I said, looking down at the sand as I spoke, so I didn't have to see their shocked expressions, and I could pretend I hadn't noticed the gasps at what I'd said. I guess they didn't know they were a well-known ocean myth that mermaids studied at school.

Two long, thin, bright yellow fish wove in between us all, as though having a slalom race with each other. "We decided to go in different directions and meet up again in ten minutes," I went on. "But then I got dragged down this kind of underwater waterfall and couldn't get out again." I looked up at Nerin. "Then you found me and brought me here."

Nerin turned to the others. "We need to find this Shona," she said ferociously, the nice act all but gone now. "We must have her!"

Amara pursed her lips into a frown. She glared into my eyes. "Try, anyway," she said.

"Try what?" I asked.

"Sing," she said simply. "Do it." She turned to the others. "You never know, she might just be over-modest, after all. It's worth a try." She turned to Nerin. "Go to the place," she said. "Hurry. And come back immediately if anything changes."

Nerin hurried away and we waited in silence.

What was she talking about? What place? And what were we waiting for?

Before I had time to ask, she'd turned back to me. This time there wasn't even a pretense of a smile. She waited for a minute or two, and then her lips rolled into a snarl. "Come on, child," she said. "Sing."

I had no choice. Anyway, what harm could it do to try? Except that my mind seemed to have gone completely blank. I couldn't think of a single song.

"Sing!" Amara repeated impatiently. "What are you waiting for?"

My mind grasped the only thing it could think of. A nursery rhyme.

"Twinkle, twinkle, little star," I began. It didn't come out how I'd hoped. I cleared my throat. "How I wonder what you are."

I stopped. The mermaids were all looking at me, their faces an identical picture of horror.

Amara was the first to speak. "What in the ocean's name was that?" she spat.

"I told you I can't sing," I protested.

Moments later, Nerin swam back into the clearing and joined Amara. "Nothing," she said. "The force is just as strong. We need to find the other one. This Shona. If the two came together, she must be nearby."

"And if they really are such good friends, surely she'll come looking when she realizes her best friend has gone missing," Amara added. "We need to find her."

"You're right," Merissa said, her voice dripping with desperation. "She can't be far away. We should split up and go in search of her."

The five of them talked among themselves at the other side of the clearing, hatching a plan to find Shona. I could hear s.n.a.t.c.hes of their conversation, but none of it made any sense to me.

"We have to find her!" one of them was saying. "Maybe she will have the voice that can get us out of here. We need to hear her sing."

"This is our best chance in years," another replied.

"Our best chance ever, you mean," the third added. "Find this siren and it could all be over."

"As long as she came in."

"We need this siren to get out of here."

I swam toward them. "What are you talking about?" I asked. "I've got a right to know!"

Amara threw her head back and laughed. "A right? You want to talk about rights, do you? Ha!" She swam straight up to my face and stared into my eyes. "I'll tell you what we're talking about, you useless disgrace of a merchild."

I flinched as though her words had hit me. I didn't speak, though. I waited for her to continue.

"We're stuck here. You'd probably figured that much out for yourself. We don't know why, and we don't know how. And after all this time, we don't even know when."

Morvena swam toward Amara. "Come on, it's not the girl's fault," she said. "Let's -"

Amara shook her off. "And not only that. Every one of us has been stripped of our singing voice," she went on. "Do you know what that means to a siren? To the best sirens known for miles and miles around?"

"Amara, you know we weren't the best," Morvena said. "Melody was the best. We backed her. It's not -"

"That's right. Stick up for Melody, just like you always do. Not that she ever bothers to stick up for herself nowadays."

"She doesn't even show herself nowadays," Nerin added.

"Too good for us, isn't she?" Amara sneered.

"Come on, now. Let's not fall out," Morvena said. "I thought you wanted to find the young siren."

Amara turned away with a swish of her tail so sharp it was like a scythe slicing through the water.

"You're right. We're wasting time," she said. "Let's help the others."

"What about the girl?" asked Nerin.

Morvena broke away from the others. "I'll see to her," she said quickly. "You go ahead. I'll follow."

The sirens exchanged a glance. "All right," Amara said finally. "Put the child somewhere safe. We can deal with her later." With that, the three of them swam away. Morvena nudged me in the opposite direction. "Come on," she said.

"What do you mean, you'll see to me?" I asked as we swam up to the top of the clearing and along a dark ledge that ran the length of the walls.

"Don't worry. I'm not going to hurt you," Morvena said. We swam along the ledge in silence, swimming past dark holes and caverns all the way along.

We pa.s.sed a low cave with jagged rocks hanging in its entrance like a jail door. Green stone walls were decorated with pink ferns dangling down like a feather curtain; ledges with fat pillars stood on either side, and stone hills sloped down, lined with pillars and rocks in a hundred different shapes and sizes.

Morvena stopped in front of a large opening. "We're here," she said. "Come on." She swam into the recess. I followed her to the entrance and looked around. Huge purple leaves fanned out around the sides. Bushy green moss formed spongy seats in one corner. A jelly-like bed ran along one side. A large rock was piled high with what looked like homemade jewelry made of driftwood and stones.

Morvena indicated for me to swim inside. "This is my room," she said as I looked around. "Stay here." Then she smiled at me. It wasn't the way the others had smiled. She wasn't snarling. "You'll be fine," she said. "Just wait here."

"And what if I don't want to stay here?"

Morvena smiled again. "Then don't," she said sweetly. "But I'm afraid you won't be able to get out. This is as pleasant a place to wait as any, until you can leave." She looked down, and her tail swished nervously in the sand. "If you can ever leave," she added.

I didn't reply, but as she swam away, her words gradually sank in. If I could ever leave? What did she mean?

The more I thought about it, the worse it looked. The lost sirens had been here for years and years, according to Shona's teacher, and now I'd joined them. A cold shiver shot through me as I realized what I'd done.

I'd found my way in here, but getting out seemed impossible. And unless Shona managed to perform some kind of singing miracle, it looked as if there could only be one conclusion.

I was going to be trapped in here with them forever.