An hour later I am sitting on the wood dock that leads from Nina’s backyard into Eel Pond. My feet are dangling in the clear water. Tiny minnows swirl around my toes. The name Eel Pond sounds icky, like something might swim up and wrap its slimy body around my feet at any minute. But Eel Pond is nothing like that. It’s one of my favorite places on the entire island.

Clang. Clang. Clang. The old bell that stands on a wooden pole next to Nina’s house rings out. Three rings means dinner’s ready. Usually the bell sounds happy, like it’s bouncing off its iron shell, excited to do its one job of the day. But tonight it sounds sad. Like it’s trapped. Like the bell knows it’s being left behind.

“Dinner!” I yell to Nina. Except she can’t hear me because she’s underwater. When her head pops up above the surface, I try again. This time she hears.

“Let’s do one more round,” she says, wiping the water from her eyes. “Just a quick one.”

“Okay,” I say. My stomach is rumbling, but I hate the thought of going inside. “You go first. I’ll follow.”

We are playing mermaid sisters, which is like regular swimming except with special chin-tucked dives and joined-leg kicks. My favorite part is going under the water and feeling it flow over the top of my head and down my body. Because when I do that, I don’t think about anything except arching my back and coming up for air.

Nina dives in front of me, her pointed toes making tiny splashes as she kicks herself down. Usually we only go to where the water lines up with the edge of her backyard. About nine dives. But Nina gets to nine and keeps going. I don’t know if she realizes how far she’s gone. I don’t call out for her to stop. All I think about is staying close. Diving down, arching up. The water flowing through my hair and over my body.

When Nina finally pauses, we are almost three houses away. We rub the water from our eyes and I see exactly where we are—outside of Sophie’s house. Sophie is one of the meanest girls at our school. She wasn’t always that way. Last summer she’d swim over to Nina’s dock and play mermaid sisters. But she’d never do that now. To make things worse, Sophie’s with her best friend, Amelia. They are sitting on Sophie’s back porch. There’s a plastic bucket between them and their legs are covered in white shaving cream. They take turns passing a razor back and forth. The razor leaves behind a stripe of shiny skin as it moves up their legs.

“Let’s go back,” says Nina. “They don’t see us.”

I nod. “Swim for as long as you can underwater. Don’t come up until you have to.”

But as I take a deep breath to fill my lungs, Sophie calls out: “Hey, Nina. Is it true that you’re moving to New York City?”

Nina and I look at each other, trying to decide what to do. We could turn away and swim back to Nina’s dock. We could fill our cheeks with water, run to the shore, and spit a long stream of Eel Pond right into their faces. But that’s not the way it works with Sophie and Amelia. Their eyes are so steady they make us feel trapped, like we really are mermaids who’ve been caught in a net.

“I’m totally jealous,” says Amelia.

“Me, too,” says Sophie. “Everybody lives there. You’ll probably run into tons of celebrities on your very first day.”

“Maybe,” says Nina.

Nina’s legs slow. I don’t know if she realizes that she’s drifting closer to shore. I have to paddle to stay by her side.

“And I bet you’ll be super popular at your new school,” says Amelia. “Everyone’s going to think you’re way exotic.” Sophie bunches her eyebrows together, confused. But even from the water I can see something brewing in Amelia’s eyes. Then Amelia says, “I mean, how else are you gonna explain the fact that you act like you’re from a different planet.”

“OMG,” says Sophie, laughing. “Tell everyone you just moved from Planet Loser. They’ll all love you! It’s too bad you can’t bring your pet dog Rover with you. That would complete the look perfectly.”

Nina freezes. The water around her stills. Slowly her forehead drops under the surface, the ends of her hair floating above. There’s a rocking from under the water. It hits my feet, my legs, my stomach. My arms lift as the water around me becomes choppy. I have to close my eyes because of the splashing. So I don’t see the moment when Nina springs, but I feel its force.

When I open my eyes, Nina is on the shore.

She runs across Sophie’s backyard and lifts the plastic bucket. I can tell it’s heavy because Nina rocks back for a second before she raises it.

There is a moment when the foamy, dirty gray water floats in the air.

Then it lands in Sophie’s and Amelia’s laps.

And all I hear are screams.