"We have to get back to the cabin before the Sharkweathers get there and see Pickles' model of the bay," I hiss.

"No problem, mermaid."

Pierce rises from the bushes, lifts me, and we shoot into the night sky. We are flying so fast; the air is like needles on my skin. "My window is open. We can go in that way." We shoot into the girls' bedroom. "Pickles! The model," I yell as soon as we are inside. We touch down on a pile of clothing. I hear the front door of the cabin creak open. Oh, no! We're too late! I yank open the bedroom door to the common room.

Panicked, I scan the room. Pickles, Fintan, Thunder, Lily-Bella, and Cupid (wearing red footie pajamas and a bow tie) are sitting on the sofas eating fairy cakes from a silver platter that occupies the space on the table where the model had been. They're acting super relaxed and casual. I breathe a sigh of relief. How did Cupid get here without us noticing him coming down the path? Gods!

"What model?" Shelly says. Ugh, she heard me yell? She and her dad are standing in front of the open door. He's frowning at me as if I've entered Poseidon's Temple without my shells. Shelly doesn't look quite right. Her skin is loose, kind of like she's molting. I would feel really bad for her if I weren't so scared right now.

The wind moans through the open door and blows apart the delicate strands of fairy lights. Each point of light turns out to be an actual fairy. They stick out their tiny glowing tongues at Pickles. Shelly and her dad have to duck to avoid the fairies as they stream out. Brack Sharkweather closes the door behind them. Now the only light in the room is from the fire, its red flames reflecting off the walls.

"Hi, Shelly. Mr. Sharkweather. Fairy cake?" Lily-Bella asks innocently.

"Hello, Waverly; Pierce," Cupid says, his mouth full of cake. "Have fun?" He's wriggling his blonde eyebrows at us.

My face heats.

"Miss Fishwater," Brack Sharkweather snarls. "I am going to have to report your behavior to the headmaster. Having a boy in your bedroom is strictly prohibited. I will see they put you on probation and will not be allowed to leave school grounds for a month. I am very disappointed in you, Waverly, for giving merfolk a bad name with your promiscuous behavior."

Shelly laughs.

I really hate her laugh, and yes, I get the irony of her dad accusing me of promiscuity, while his daughter stands there in a bustier and miniskirt, her golden-green hair once again in a ponytail that exposes her neck like a vampire invitation. "Mr. Sharkweather, nothing happened between Pierce and me. And why am I the one being punished? What about Pierce?"

"Vampires aren't my problem, Miss Fishwater." Mr. Sharkweather spat these words, making his opinions on vampires very clear. Funny that he's kissing up to Headmaster Crumpet. "Shelly, I'll see you on the yacht for dinner tomorrow night with the headmaster." He glares at all of us and walks out of the cabin, the door banging closed behind him.

Shelly smirks at me, swipes three fairy cakes, and takes them into the bedroom, slamming the door. A moment later we hear the water running in the shower.

"I'm on probation?" I whisper. "Can't leave the grounds? How are we going to spy on the yacht if I can't get off campus?"

Pierce grins, giving me the urge to smoosh cake on his face, so I don't have to see him gloat. "I guess I'll have to do it."

I show a great deal of restraint in not reaching for a cake. "No way, Knightguard. I will figure out a way. Tomorrow night, we're going on a shark hunt. I'm going to take down Sharkweather, and no one is going to stop me."

"Then, can I tie him to a tree and question him?" Thunder pleads.

"Yes," I say. "And I'm going to be the one handing you the blunt objects."

"Ooh," Cupid coos. "I'll help."

The only good thing about math class today is that Dad is having it on the beach because it's a sunny, gorgeous day. The bad part (other than the fact that my dad is the teacher, and half the girls in the class are mooning over him right now, urgh!) is that we are having a lesson on infinity. With sand. We are dropping the grains into buckets with tweezers and keeping count.

My dad thinks this is hilarious.

"Whoever gets to infinity first is the winner," my dad says encouragingly.

"Dad, we already know we can never reach infinity. Can't we do something more fun now, like Euclidean geometry or gouging out our eyeballs with our tweezers?" I say this out loud, so my fellow students know that I am not on board with the whole sand-counting exercise.

"Oh, come on, Waverly," my dad says telepathically. "This is fun. Math is fun." I can tell he's telepathically willing me to believe this statement.

"Dad, I'm not six," I reply. "I've known the true nature of math for years now."

"You have?"

"Yes. It's a conspiracy, conceived by adults for the purpose of making the lives of their offspring a living hell."

My dad shakes his head. He looks really disappointed. "Look, Dad, I'm sorry I didn't get the math gene, okay?"

"It's alright, Wave. Maybe your new baby brothers and sisters will like math."

Shelly is watching us, her eyes narrowed. I really didn't want her to know about my mom being pregnant. A horrible vision flashes through my mind of my mom and the babies suffering. Someone is making my mom cry! I drop the tweezers and start to shake.

"Wave, are you okay?" Pierce says. He leaves his bucket and holds my face in his hands.

"Yeah, I'm fine." I force a smile because everyone is looking at us, including my dad. I pick up the tweezers. "I'll tell you later," I whisper to Pierce.

I try to calm myself. Hopefully, this isn't a real fairy prediction that might come true. I'm sure my mom and the babies will be fine. Babies! Urgh. It's bad enough losing my spot as the cute, youngest fingerling—now I might have a bunch of adorable younger siblings to steal all the limelight!

I notice Shelly looking at me again. "Stop poking around in my brain," I tell her. "It is incredibly impolite."

She grins and resumes her counting. I pick up a grain of sand and drop it in the bucket. "Seventeen thousand one hundred and twenty-two. Seventeen thousand one hundred and twenty-three ..." I'm concentrating on the numbers as hard as I can to keep all other thoughts out of my head.

A blur suddenly sweeps across the beach, kicking up sand, and stops next to my dad. It's Headmaster Crumpet. Oh, no. I hope he's not here to take me into custody for last night right in front of my dad!

"I'm sorry to disturb your lesson," Headmaster Crumpet says. "But might I have a word with the class?"

"Of course, Sir," my dad says. It is weird that he is being all deferential toward someone who looks twelve years old.

"Thank you, Gil." Headmaster Crumpet turns to face the class. "Sorry to interrupt what looks like a fascinating exploration into the world of sand, but I have an announcement which I think you will all be quite happy to hear. Most of you are new and do not know about the West Marin Heights annual Halloween gala. Being an all-vampire school for so many years, you can imagine that Halloween is a very important holiday for us. There will be no classes that day, so everyone can prepare. There will be prizes for the best costumes, so you should all think about what you would like to be."

Everyone chatters excitedly. It sounds really fun. And I am relieved the headmaster isn't here to take me off to lifelong detention in front of everyone.

"The school board has nominated two students to be in charge of the event. They will form a committee to help with the planning. Serving on the committee is a great honor. The committee heads are ..." Headmaster Crumpet scans the class. "Cupid ..." The class erupts in applause. Kind of an obvious choice if you ask me. Cupid is an ancient god who's related to Dionysus, the original party god. Cupid rises and gives us a bow. "... and Shelly Sharkweather."

My heart sinks. Shelly stands and curtsies. She's grinning. I can tell she already knew she would be chosen. Suddenly this party doesn't seem like it'll be that fun. The applause for Cupid dies out.

"Shelly, who would you like to serve on the committee with you?" Crumpet asks.

"Hmmm. I think I'd like Pierce and Lily-Bella." Everyone claps and hoots.

What? Shelly wants Pierce? I thought she knew we were done with that game and that she had clearly lost. I look at Pierce, silently begging him to decline. Instead, he and Lily-Bella get up and stand next to Shelly. Pierce looks at me. I can tell he's trying to tell me something, but I can't figure out what.

Crumpet claps. "Excellent choices, Miss Sharkweather. And Cupid?"

"I choose Waverly and Fintan." Everyone throws their buckets into the air and cheers. Sand flies everywhere. I am thrilled that now I can monitor Shelly during the party planning and that the class is so happy about Fintan and me being on the committee. But why did they have to toss their buckets? Now we are going to have to count to infinity all over again. This class really is going to be infinite.

"Excellent choices, Cupid. The committee will have its first meeting right after math class today. We need to secure a venue right away. Again, I apologize for the interruption." Crumpet's eyes scan the class again. "Waverly?"

"Yes, sir?"

"Could you please accompany me to my office?"

Oh, no! Please don't say anything in front of my dad. "Sure. No problem," I say.

"Is it okay if I borrow your daughter, Gil? We have a few things to discuss."

"Of course."

"What's going on, Waverly?" my dad asks me.

"I have no idea, Dad," I lie. By the way, telepathic lying is a whole skill unto itself. As a teen mermaid, I have gotten pretty good at it, but under stressful circumstances like this, it is really difficult.

His mouth tightens into a straight line. "We will talk later."

"Sure, Dad," I say in my most casual, unworried tone. I glance back at Pierce over my shoulder.

"It'll be okay," he mouths.

I'm following the headmaster up the beach, relieved I've gotten away without utter public parental mortification, when I hear Shelly say out loud, "Waverly was caught alone in our bedroom with a boy last night."

Maybe I can get Thunder to tie Shelly to a tree along with her father. Luckily, Headmaster Crumpet and I are too far away for me to make out Dad's telepathic response.

"Please have a seat," the headmaster says in a high-pitched childish voice, despite the fact that he is probably about a million years old. He points to a small wooden chair facing a desk so huge it takes up half the room.

I settle in as Headmaster Crumpet stokes a dying fire in a wood-burning stove in the corner of his cramped office. The room smells like wood-smoke and old paper, and the light from a dull, yellow lamp makes everything look old and kind of sad. The walls are lined with shelves crammed full with toys still in their boxes. There are paddles that have red balls attached with strings, colorful clowns standing in boxes, stuffed animals like the ones you can win at the boardwalk arcade, red cars, blue airplanes, long strings of connected railway cars, blocks, games, kaleidoscopes, and a hundred more things I've never seen before.

A cold lump forms in my throat. This is a vampire who never got to be a boy. He didn't have a real childhood like I did, where he could play Pass The Jellyfish with his best friend, or break a bunch of his mom's ugly shell bras and hide the pieces inside a scalding hydrothermal vent so she'd never find them.

He takes a seat behind the massive desk, his small head peeking over the top like a fingerling trying to ride a blue whale.

"Waverly, I brought you to my office because I want to chat with you about the school policy regarding dating." He stares at me intently with those cornflower-blue eyes, and I squirm a little.

"There's a policy? I hadn't heard that before."

"It's rather new," Headmaster Crumpet says, coughing. He picks up a pile of small, metallic beads from his desk and forms them into a three-dimensional shape, like a hexagon or pentagon or whatnot (I would know the name if I wasn't math-intolerant). But what I do know is that the headmaster is no longer looking me in the eye. He's hiding something. Which of course means, I have to find out what it is.

"Nothing at all happened with Pierce. Mr. Sharkweather just hates me." I cleverly bring up Sharkweather's name to see Crumpet's reaction.

"No one hates you," he says, defending Sharkweather. Hmmm. Very sketchy. "I am afraid you are confined to campus for the next month. But that shouldn't be a problem, right?" He looks at me with a serious expression. "You don't need to leave the school grounds, after all. We have everything you need right here, and I don't want to see you get hurt."

"What do you mean?"

"Only that fairy princess Iridessa has set some new, highly unbreakable, and rather nasty fairy spells at the campus borders. And don't bother using Pickles to wish the spell away. Princess Iridessa's enchantments are stronger than any fairy godmother magic. We've always had human deflection spells in place to keep non-magical beings from discovering the school, but now, I'm afraid, they have been enhanced to keep the students contained."

My jaw drops. "You know about Pickles being my fairy godmother?"

"I know everything that happens at this school."

"You can't hold me prisoner."

"This is high school, Miss Fishwater. Of course we can."

Is Crumpet working with Sharkweather? I can't believe it. But why else would he be acting this way? I am so glad we didn't share our findings about the water being poisoned with the headmaster.

"Is that it? I should get back to class."

"That is all, Miss Fishwater."

I stand, the chair scraping against the wood floor. "Uh, thanks," I say, then I practically run back to math class. If you'd asked me yesterday whether I would ever rush toward math, I'd have said you were crazy. But I need to see my friends. Tonight, I am sneaking onto that yacht. Period. And I will figure out Sharkweather's dastardly plan.

Now all I have to do is figure out how to break an unbreakable fairy spell. But hey, it can't be as hard as counting sand!