"So swish, Neptune coming to our school," Althea murmured.

"I know," Shona replied dreamily.

"I wonder if he'll get all his treasure back," Marina added, and the three of them talked about his visit all the way to the end of the tunnel, where Shona and I said good-bye to the others.

As soon as they were out of sight, Shona turned to me, her eyes almost popping out with excitement. "So? What were you trying to tell me this morning?" she asked. "Was it about the ring? Did you really lose it?"

I glanced around before replying. Some younger merchildren were laughing and playing in the sea on their way home from school. A couple of them had caught a ride home on a dolphin. Others were chasing one another or jumping over waves. The sun beat down on us.

I pulled Shona into a rocky crevice. We swam between the rocks, taking a long route home. Once I was sure there was no one around, I pulled my hand out of my pocket. It slid out easily this time. Twisting the ring around so she could see the diamond, I held my hand out.

"Swirling sea horses!" Shona said, swimming up to look more closely. "You had it all along! But why did you say you'd lost it?"

I wondered whether to tell her the truth about the weird feeling I'd been getting from it all day. How crazy would it sound, though? And was it a good idea to involve her at all? Last time I'd dragged her into one of my adventures, it had nearly wrecked things between us. But could I really go through this on my own?

"You promise not to tell anyone about this?" I asked, deciding our friendship was strong enough.

Shona looked at me blankly. "Why? Why the big secret? How come you didn't turn it in, Emily?"

I shook my head. "I couldn't."

"*Didn't want to,' you mean?" Shona said. "Emily, you heard what Mr. Beeston said. Neptune will be furious if anyone a""

"I couldn't, Shona," I said more firmly.

She stopped and stared at me. "Why not? What do you mean?"

I looked up at her from under my eyelids. I could feel my tail quiver as I blushed. "You'll think I'm crazy," I said.

"Of course I won't," Shona said, laughing. "I know you're crazy. Come on, it's me, your best friend. Tell me!"

I smiled, despite my weird feelings about it all. "OK." And before I could talk myself out of it, I found myself telling Shona all the things I'd been feeling since I'd been wearing the ring and about my hand getting stuck in my pocket while Neptune was at school.

"It was so strange, when I was looking for it. I had such a strong feeling, as if it wanted me to find it," I said.

I stopped talking and waited for Shona to speak. This was where she would tell me I'd completely lost it and she didn't want to be my friend anymore. Why had I risked her friendship again? Was it too late to take it all back, say I was joking?

I stared down at a skinny sea horse bobbing along the seabed, its bright orange color standing out against the white sand. A shoal of b.u.t.ter hamlets drifted by, taking no notice of the sea horse or of us.

Finally I looked up at Shona. She was staring into my face. "You promise you're not making this up?" she asked.

"Of course I'm not making it up! Why would I want you to think I'm even nuttier than you already do?"

"It must be magic, then," she said, her eyes shining with delight. "It's so beautiful," she added with a touch of envy. "Can I try it on?"

I laughed. I might have known Shona would want to try it for herself.

I tried to pull it off my finger, but it was stuck. I pulled harder a" and a rushing noise flooded into my head. Thundering and rolling. What was it? There was a storm raging out at sea. I could feel it. Waves crashing everywhere, thunder booming into every corner of the sky, lightning cracking the world open. And grief. I wanted to cry. Wanted to break down in floods of tears and cry till I'd filled an ocean. I squeezed my eyes shut, stopped trying to pull the ring off, and clasped my hands over my ears.

Instantly the storm stopped.

"What was that?" I asked.

"What?" Shona looked bemused.

"The storms, the sea crashing."

"I don't know what you mean," Shona said. "I didn't feel anything." She looked at me sideways for a second, then shook her head and examined the ring again. I flicked my tail to stay upright and still as she stared at it. Was she joking with me? How could she not have noticed the storms? "It's really the swishiest thing I've ever seen," Shona breathed, staring at the ring as though it were the only thing in the world.

"I can't get it off," I said.

"Here, let me try." Shona reached out and I held my hand open for her. But the second she touched the ring, she catapulted away from me as though she'd been shot out of a cannon, landing in a bunch of mossy seaweed.

I swam over to her and pulled her out. "You all right?" I asked.

"It burned me!" she shrieked, pointing at the ring. "Or bit me, or something!"

I yanked at the ring again. "Don't be silly. It's just a""

"I don't want to try it! You keep it. It's fine." Shona dusted her tail down, wiping sand and moss from her scales.

I twisted the ring back around on my finger so the diamond could stay hidden against my palm. I felt safer with it that way.

"Come on," Shona said. "Let's go back to your place and do our homework."

She swam off without another word.

I knew as soon as we reached Fortuna that something was wrong. The first person I saw was Millie. Not that that was so unusual. She often came over to see Mom.

But she was on her own, sunning herself on the front deck. If "sunning herself" is the right expression. Millie must be the only person in the world who manages to sunbathe in a long black gown. She never wears anything else. She'd pulled it up to her knees and was stretched out on a blanket, a packet of cards spread out in a star shape next to her.

"Where's Mom?" I called as we approached the boat.

Millie looked over and squinted into the sunlight. Sitting up and pulling her gown back down to her feet, she shuffled the cards into a pile. Shona and I swam up to the side of the boat. "She had to go out," Millie said in the mysterious way in which she says everything.

"Had to? Why? Where?"

"She just a" look, it's not really for me to explain."

"Fine, I'll ask Dad."

I swam to the front of the boat and was about to dive down to the porthole when Millie said, "He's gone out too."

I stopped, treading water with my tail. "They've gone out together?" I asked hopefully, knowing even before she spoke what the answer was going to be.

"No." She refused to meet my eyes. "No, they've gone out separately. Your mom asked me to wait here for you. I thought perhaps we could play canasta, or I'll do your tarot cards for you, if you like."

"They've had an argument, haven't they?" I asked.

Millie still wouldn't look at me. She started dealing out the cards for a game of patience. "I really think you need to talk to your parents about it," she said awkwardly. "I just don't think it's my place to a""

"It doesn't matter," I said, cutting her off. "Come on, Shona, let's go inside."

We swam silently through the porthole into the downstairs floor of the boat, the part that was filled with water, where Dad lived. I knew exactly what Millie was telling me or, rather, what she wasn't telling me. It was obvious they'd had an argument. They'd been heading in that direction for days.

I'd managed to push the morning's fight out of my mind for most of the day, what with everything else that had been going on. But now, well, that was it. They'd walked out. On each other, and on me too. Was it because of me? If they didn't have to argue about how to bring up their daughter, everything would probably be fine between them.

I know, I know. Overactive imagination again. I was probably blowing it out of proportion. But what if I wasn't? I just couldn't stop the questions from pushing everything else out of my mind. What if they really were going to separate? What if neither of them ever came back?

Shona tried to humor me out of my mood by making silly faces behind the fern curtains and offering to share the bottle of glitter she'd brought home from school. But it was no good. Nothing could lift the heaviness of my mood or the dark cloud of my thoughts.

Mom and Dad were going to split up, and it was all my fault.

"Emily, are you down there?" Millie called from the kitchen.

I raced up to the little trapdoor. Maybe she wanted to tell me Mom and Dad had come home! "Are they back?" I asked.

"I a" I'm sorry, dear," Millie said. "I was just thinking I'd make us a snack. I thought you might be hungry."

I suddenly felt empty, but not from hunger.

"No, thanks," I said sullenly, and slipped back down without waiting for her to reply. I twisted the ring back around and studied the diamond, as if it could make me feel better.

Shona was busy painting swirly patterns on her tail with scale polish. She looked up as I swam back toward her.

And then it happened. The shaking, the rocking, waves rolling over one another; even the boat seemed to be moving. Water sploshed in from the trapdoor above us.

"What's going on?" Shona shouted, smearing the swirly patterns into a smudge down her tail.

"I don't know!" I called back, half relieved that at least I wasn't imagining it this time. "Hold on to the porthole!"

We swam as hard as we could to get to the front end, where the large open porthole seemed like the steadiest thing to hold on to. Gripping the sides of it, our tails flailing out all over the place, we waited for the shaking to stop.

"Are you all right down there, girls?" Millie's voice warbled from upstairs.

"We're fine!" I yelled back. "Hold on to the rails, Millie!"

"I am!" she replied. "I'm fine. It'll be all right, don't worry," she added, her voice wobbling with fear. "I'll take care of you!"

Though we gripped the sides tightly, our bodies were flung from side to side, our tails. .h.i.tting the wall as the boat rocked and shook. It was like an underwater roller coaster ride! Up, down, thwacking us all around, the motion slapped our bodies backward and forward in the water so violently I was nearly sick.

And then it stopped. Just like that. The boat stopped rocking. Shona and I looked at each other for a moment as we became still. Just for a second.

In that second, a sharp pain stabbed my hand. The ring! It was digging into my finger! Aargh! I curled my hand into a ball, the diamond tight inside my fist. Catching my breath, I looked up to see a dark shadow fall over the porthole.

Something was outside. Something big. And it was heading toward the boat.

"I might have KNOWN!" The voice boomed into the boat like an explosion.

Surely this couldn't be real. Neptune! He was outside the boat, his chariot gleaming in the sunlight, dolphins surrounding him as he raised his trident. The sea around him bubbled like burning lava.

"Come HERE!" he bellowed.

I looked around, desperately hoping I'd spot who it was that he was addressing. I mean, it couldn't be me. It couldn't be. What had I done this time? Surely this wasn't about the ring!

"Yes," he growled in a quieter voice that was even more threatening than a shout. "You." He pointed directly at me.

I swam through the porthole that we used as the underwater door, my tail shaking so much I thought it would fall off.

"Alone!" Neptune barked as Shona approached the porthole behind me.

"I'll wait here. You'll be OK," Shona whispered, sounding as if she believed it about as much as I did.

I wobbled toward Neptune like a jellyfish and waited for him to speak.

But he didn't. He just stared. Stared and stared at me until I wondered if he was going to turn me to stone with his eyes. But he wasn't even looking into my eyes. He was looking at my open hand, at the diamond.

"For once, Beeston did well," he said in a quiet voice. Quiet for Neptune, anyway. It still vibrated through the air, splashing water across the sides of his chariot with each word. "All those years and it was right here," he murmured even more quietly, his eyes still fixed on the ring.

My hand burned under his gaze. It felt as though it were on fire, flames scorching through my fingers, screaming along my arm, into my body, all through me. I clenched my teeth and waited.

Eventually, Neptune raised his head to look me in the eyes. "Remove it," he said simply, holding out his hand.

"I a""

"The ring. Give it to me. NOW!"

As he waited for me to hand over the ring, the sea rocked and ebbed around us. I bobbed around, bouncing up and down in the water while I fumbled and pulled at my finger. My hands shook with terror. I couldn't do it. The ring was completely stuck. My finger swelled and throbbed.

"I a" I can't," I stammered, my words jamming through the thudding in my mouth.

At this, Neptune rose higher in his chariot. As he did, the waves grew sharper, splashing against me, slapping my face, pulling me under. "Come here," he said. Swirling my tail around as hard as I could, I propelled myself back up and swam toward the chariot.

Neptune held his trident in front of me. "Put your hand out," he said. I did what he said. Then he reached toward me with the trident and touched the ring.

The result was electric. Literally. I felt as if I'd been struck by lightning. My body zipped into life as though a thousand volts were buzzing through every nerve. Neptune must have been struck too. His beard seemed to have flames flying from it. His tail was shooting sparks out in every direction. A jagged orange light danced and crackled between us, alive and on fire.

Neptune finally pulled the trident away. Breathless, he paused to gather himself. Then he reached out with his hand. Grabbing my wrist, he pulled at the ring.

"AAARRRGGH!" he screamed, leaping backward. He shook his hand, blew on it, plunged it into the water. As he did so, the sea raged around us, building into the worst storm I'd ever seen. Clouds darkened, blackening the sky, closing down on us. I was being tossed around everywhere. Even Fortuna shook so violently that it was starting to break free from the spot in the seabed where it had been deeply stuck for more than two hundred years. The boat heeled madly from side to side.

"d.a.m.n those vows!" Neptune bellowed. "They were not meant to prevent me from touching the rings! I am the king of all the oceans!"

What did he mean? What vows? Why couldn't he touch the ring?

As if he'd heard me, Neptune snapped his head around to face me. "That ring has been out of my sight for hundreds of years," he said. "And that is exactly where it should have stayed. Never have I thought of it in all those years. Never. Not once did I question its whereabouts." He laughed sardonically. He wasn't smiling, though. "Although I should have known the kraken would have found it and protected it. The kraken understands loyalty."

Neptune looked up to the sky. "It should have remained hidden, out of sight, buried in the seabed," he called to the clouds, which split apart and cracked in claps of thunder. "I need it to be buried, along with everything it represents."