"With her plans to make the school stricter," she said darkly. "If I'm right, I bet you anything the school's just gotten a new rule."

"What rule?" I asked, although a part of me knew what she was going to say. I just couldn't help hoping I was wrong.

Shona looked at me almost guiltily before confirming my suspicion. "No semi-mers."

"Now, children, I would like you all to listen very carefully, and watch closely." Mrs. Sharktail had canceled afternoon cla.s.ses and gathered the whole school together in the main chamber for a special afternoon a.s.sembly.

I was guessing we were the "special" bit.

I looked around. A hundred mergirls and boys looked back at me. I tried not to meet anyone's eyes, focusing instead on the pillars all around us, the light glinting in shiny purples and greens on the water, the rocks and boulders lining the sides of the chamber.

"As you know, this is a traditional mer-school," Mrs. Sharktail went on. "We have traditional rules and we teach you, to the best of our ability, in all things mer, so that you may all grow up to be wonderfully gifted, competent, and happy merpeople. Is that not true, staff?"

She looked across to the teachers lined up along one side of the chamber. They all nodded fervently back at her.

"I'm sure all of you are aware that our community here at Shiprock has recently been under threat from humans."

I don't know if it was just me, but I was sure that she said the word humans as though something disgusting had gotten stuck in her throat.

"They are hovering around the edges of Shiprock, barging into areas that don't belong to them, and are one step away from breaking into our town like burglars. At a time like this, it is more important than ever to protect our community. Would anyone like to disagree with me?"

When she put it like that, it was pretty hard for anyone to disagree. But she was making it sound as though humans were purposely trying to destroy Shiprock. As though they knew what they were doing. Mr. Beeston had already done some research, and the one thing he was categorically sure of was that the builders didn't have the slightest inkling that there was a town of merpeople not far from where they were building.

He'd shown us what he called his "interim findings" the night before. Apparently, the council was planning to build new houses, but they'd discovered weaknesses below ground level. They'd investigated further and discovered that the land they'd been working on formed the roof of some impressive caves and tunnels.

What they didn't know was that the tunnels stretched out for miles and that one of them led all the way to Shiprock.

The building work had been halted while the council decided what to do next. They were going to do one of two things: either fill in the caves completely, to make the ground stable enough for them to stick with the original plan to build houses, or change tack altogether and dig the caves out as far as they could and open them up as a tourist attraction.

Either option spelled utter disaster for Shiprock.

The first could result in ma.s.sive underwater landslides that would probably destroy the whole town. The second would almost certainly lead to Shiprock's discovery - meaning the inhabitants would have two choices: become a freak show to entertain humans or leave their homes forever.

The interim findings had not been good.

So Mrs. Sharktail had even more reason to hate humans than she realized. She didn't know Brightport's exact plans, but she could feel the effect of them - like everyone else in Shiprock.

"Good," Mrs. Sharktail continued, looking around at the school with her version of a smile. It was like a jagged little line across her face with the tiniest upward curl in each corner. "In that case, you will understand why we have recently tightened our school rules."

Shona was right, then. Aaron and I were officially against the rules.

She went on. "And you will doubtless share my horror at a discovery I made earlier today." She swam a few strokes in our direction.

Every eye that wasn't already on Aaron and me turned toward us now.

"Humans!" she exclaimed in a tone that couldn't have dripped with more venom even if it had come directly out of a snake's mouth.

Her accusation was only tempered by one small detail: the fact that Aaron and I were as mer as anyone else when we were in water. I noticed a few puzzled looks pa.s.s between some of the girls.

"Yes, well, not now they're not," she snapped. "But they were. Semi-mers," she said with that same disgusted tone that I was starting to get a bit sick of. "To think - coming to my school, and I didn't even know it. Luckily for all of us, the issue has recently been rectified."

The issue had been rectified? These were our lives she was talking about! We weren't some problem that needed fixing. I'd had enough. I had to say something. If I could stand up to Neptune in his own court, which I had when I'd rescued my dad from prison, then surely I could speak out now.

"We haven't done anything wrong," I said in a voice that came out much smaller than I was expecting. I cleared my throat and tried again. "Semi-mers aren't against the law. Neptune's even changed all the intermarriage laws. He wants humans and merfolk to get along."

With the slightest flick of her tail, Mrs. Sharktail whizzed over to me. "Did I ask you to say anything?" she snarled. She turned back to face the school. "Of course, strictly speaking, semi-mers are not against the law," she said. "Although, if I had my way, they certainly would be," she added under her breath. "But as of the last few weeks, they are against our school's rules, and at a time like this, when our ways are under such threat from humans, it is more important than ever to enforce all of our rules."

She turned back to me and Aaron. "As of this moment, the pair of you are no longer welcome in our school."

She stared at us. We stared back at her. And then, in case we were in any doubt about exactly how unwelcome we were in her school, she added in a deep rumble, "Leave - now!"

There was a swishing noise at the back of the hall. Shona! She was pushing her way past the rest of her cla.s.s to get to us. No, Shona, don't! You'll only get yourself in more trouble.

I grabbed Aaron's arm. "We're going," I said, staring into Mrs. Sharktail's sharp beady eyes. "We know when we're not welcome." Which, OK, wasn't the cleverest retort ever. You'd have to be the most ignorant person in the world not to have known you weren't welcome after all that. But I couldn't think of anything else to say.

We swam away from the stage and away from the chamber with every eye in the school watching us go. I don't think even Mandy Rushton had ever made me feel so humiliated. And to make matters worse, do you know what I heard as we swam off? Clapping. Mrs. Sharktail started it. I didn't look back. I didn't want to see how many others were joining in.

"Now what?" Aaron and I had stopped for a rest, perched on the side of a rock.

I fought back an urge to burst into tears. But the tears were there, jamming up my throat so hard I couldn't reply. I just shook my head.

"I mean, did that really happen?" Aaron asked. The sound of his voice dislodged the tears I was holding back, and they started to trickle down my face.

"Hey, don't cry," he said in a voice so soft it only made me cry harder. He reached a hand out, as if he were going to wipe the tear from my face. His hand hovered in midair for a moment, before he changed his mind and let it drop. I noticed that his cheeks had turned pink.

"We were supposed to bring the human and mer worlds together," I croaked. "What chance do we stand of doing that if the merpeople don't even want us around?"

"I know," he said. "I think we might have a harder job than we realized." And then he reached out again. This time he didn't change his mind. He stretched across and put a gangly arm around my shoulders. It felt weird. But nice. And it stopped me from wanting to cry quite so much.

"Come on," I said after a while. "We should probably go home and tell our parents what's happened."

Aaron plopped back into the water, and I followed him. As we swam slowly back, I could only hope that Mom or Dad would have some idea of what to do next. Because if they didn't, life in Brightport was about to take a nosedive.

On the way back to Brightport, Aaron asked about Brightport High. What could I say? I wanted to tell him it was great, but when I opened my mouth to describe it, all I could think of was one thing. Or rather, one person.

"Look, if we're starting at Brightport High, I'd better tell you about someone," I said. "You'll come across her soon, so you might as well be prepared."

A shoal of yellow and green fish swam beside us, gliding along with the tiniest flicks of their tails. "Go on," he said.

"Mandy Rushton."

Aaron's face brightened. "The girl who helped you save everyone from the kraken. I remember you talking about her. Hey, at least we know we'll have a friendly face waiting to see us there."

I half laughed and half choked, swallowing about a gallon of seawater in the process. "Erm, it's not exactly like that," I said. Then I explained about how mean Mandy used to be to me at school. How she used to call me names, and make fun of me, and try to get me into trouble with the teachers.

"But you made up at Allpoints Island, didn't you?"

"Well, yes, but it's not that straightforward." I told him about the memory drug that Neptune had given all the humans before they left the island so they wouldn't remember seeing the merpeople and the kraken.

"And you think the memory drug will have made her forget that you were friends?"

"Exactly."

"Is there any chance that the memory drug didn't include that part and she'll still be friends with you?"

I'd wondered the same thing myself, but I wasn't holding out much hope. "We'll find out soon enough," I said. "But I thought you should be warned, just in case."

We swam the rest of the way in silence, accompanied by a single silver fish that looked like a sword, slicing along the seabed, silent and somber.

"Jake, I want you to march right into Shiprock School and give them what for!"

We were out on the deck of the boat, and Mom was on the warpath. "Our children are as good as anyone else's, and have as much right to attend that school as all the others!"

Dad was in the sea below us. He swam backward and forward across the bow of the boat. Despite everything that was going on, it felt nice to discover that he paced when he was trying to work out what to do, just like I do. I'd only known my dad since last year, and there were still loads of things I was discovering about him.

"It's not as simple as that," he said. "I mean, they've got their rules and -"

"Rules? Since when did you give a hoot about rules when the rules are downright silly and unfair?" Mom fumed.

Dad swam right up to the side of the boat and reached out for her hand. She folded her arms.

"Penny, I'm working for Neptune now," he said. "Things aren't like they used to be."

"No," she said pointedly. "They're not."

Dad reached out farther for her hand. "Come on, don't be like that," he said. "I'm as outraged as you are. I just think we need to be careful about how we approach this."

Mom shuffled farther away. "In case you've forgotten, your new boss is the same Neptune who told us to go and bring the human and the mer worlds closer together. He ordered us to do it! He told us this would be our first test, remember? And you want to sit back and do nothing while our daughter is humiliated in front of an entire school and shown very clearly what the mer world thinks of the human one. How is that being loyal to your precious Neptune?"

Mom's face was scarlet. Why was she so angry? She hadn't even wanted us to go to Shiprock in the first place!

"It's the principle of the thing," she snapped as though she'd read my mind.

Dad's face was almost as red as Mom's. Please don't argue, I thought. I couldn't go through all that again. They'd argued so much when we'd first arrived at Allpoints Island, I'd thought they were going to split up.

"Look, I understand what you're saying," Dad said calmly. "But we're going to have to tread carefully. I'm not going to sit doing nothing while Shiprock makes an example of Emily."

"And Aaron," I b.u.t.ted in.

Dad nodded. "And Aaron. I'll do something. But I want to make sure that whatever we do, it's the right thing. If we go charging in there shouting our gills off now, how's that going to help our cause?"

Mom turned away.

Dad tried again. "Come on, Pen, we've got to be a team; we've got to work this out together. That's what Neptune instructed us to do as well."

Mom let out a huge sigh, then she sat on the edge of the deck and took Dad's hand. "I suppose you're right," she said grudgingly. "Naturally."

"Naturally? Why naturally?" Dad asked.

"Well, look at me. Who am I to think I can build bridges between people? We should tell Neptune to pick someone else."

"Mary Penelope, what on earth are you talking about?"

Uh-oh. Dad had called her by her full name. He only called her Mary Penelope when it was really serious. It was time to step in.

"Look, I don't mind all that much, now that it's over and done with," I said quickly. "I'm happy to go to Brightport High, and so's Aaron. I've told him all about it. So why don't we just forget it and carry on as though nothing's happened? We've got each other, and that's all that matters really, isn't it?"

Mom looked down at the deck. Shaking her head, she mumbled, "That's not the point."

Now it was Dad's turn to sigh. "If that's not the point, then what is?"

She muttered something.

"What was that?" Dad asked, a sliver of impatience creeping into his voice.

Mom looked up. A tear had slipped from her eye and was snaking down her cheek. "My parents," she said numbly.

Dad reached up and stroked her leg. "Oh, Penny," he said. She gulped back a sob.

"I don't get it," I said. "What about them? I thought you hadn't seen them for years."

"Exactly!" Mom said woodenly. "That's my point! What chance do I stand of building bridges between two worlds if even my own parents haven't spoken to me in more than ten years? Neptune's picked the wrong person!"

And with that, she wrapped her arms around her knees and threw herself wholeheartedly into crying very loudly.

I couldn't stand to see her like that. Seeing my mom cry felt like someone was sticking a knife into my chest. I reached out and touched her arm. "Mom, it's OK," I said, feeling completely useless.

She shook her head. "No, it's not," she said into her knees. "It's not OK at all. In fact, it's about as un-OK as you can get." She took hold of my hand and tried a feeble smile. "But thank you for trying, sweet pea."

I think Dad must have felt as useless as I did, but he didn't try to say anything helpful. He just kept on stroking her legs while we waited for her to cry herself out.

We ate a snack together in silence. It wasn't the happiest silence in the world, but at least there were no tears. And we managed to discuss the situation enough to make one decision: I wasn't going to start at Brightport High in a hurry.

Since there were only a few weeks of the school year left, Mom and Dad agreed I could wait till September. At least it meant I didn't have to worry about the risk of being equally humiliated there - not for a while, anyway.

None of us had mentioned my grandparents again. I was dying to, though. Now that Mom had brought them up, I was aware that she never talked about them and that I never asked. Except for the moment last year out at the Great Mermer Reef, when she remembered everything. She told me then what had happened with them - how they'd practically disowned her because of her relationship with a merman. But that was it; that was all I knew. I didn't actually know anything about them: what they were like, how things had been with them before it had all gone wrong. I realized I wanted to know all about them. But not now. This wasn't the time to ask.

"Can I go to Aaron's?" I asked instead, taking my plate over to the sink. I wanted to find out what his mom had said and what they were planning to do now. Hopefully she'd say the same as Mom and Dad, and Aaron and I could hang out together for an extra few weeks. Getting thrown out of mermaid school might not feel so bad, then.

I had a twinge of guilt as I realized that whenever I had some free time nowadays, Aaron was the first person I thought of spending it with, not Shona. Was it disloyal of me? Did it make me a bad best friend?

I couldn't answer either question, and I certainly wasn't going to ask anyone else. I pushed the guilty feelings away and went out.

I walked up the pier and was heading toward the cottages where Aaron and his mom were staying when a familiar figure rounded the corner. Mandy. This was it, then: truth time.

She was looking down at the ground while she walked and hadn't spotted me yet. I held my breath, waiting till she did. Or would she walk straight past me without even noticing?

Just before we pa.s.sed each other, she suddenly looked up. For approximately a millisecond, her eyes brightened. She looked as if she were about to smile. I started to smile back. She remembered!