Chapter 1

A sharp whip of salt water lashes the bow of the dinghy and smacks Mia hard in the face. With her free hand, she wipes the water from her eyes, blinking furiously to see through the warm rain. She knows she shouldn’t be out here, certainly not on a battered ten-​foot inflatable dinghy. The storm is quickly transforming the blue Caribbean into angry, darkened waves. She needs to turn back now, head for the safety of the French West Indies behind her.

Instead, she twists the throttle and accelerates into the storm.

Up ahead, she sees nothing but sheets of gray­black rain and waves that rise like terrible, shape​­shifting creatures. Her dinghy, with its puny six-​horsepower outboard motor, is like a puppy lost in the wilderness. She is already half sunk, with the pummeling rain and the boat’s floorboards sloshing with seawater. The only upside: The water on board adds weight, holding the boat down so the violent gusts don’t flip her like a pancake.

Sheets of mist streak off the tops of the waves, giving her only brief glimpses of what’s ahead. With each rise of the swell, Mia unconsciously holds her breath, hoping to spot her. But then the dinghy drops into a trough and Mia’s heart falls.

I’ve lost her, she thinks, the tears welling up.

Six months ago if someone had said she’d end up racing into a tropical storm on a rescue mission, she would have laughed. She thought high school in Duluth would just grind on forever, an endless succession of awkward days. She could never have imagined this, battling through nine​­foot waves on a small rubber boat in the Caribbean.

The salt water pours down her ­sun-​­streaked brown hair and stings her eyes, turning them bloodshot, and she laughs through the tears. She must look truly insane: red-­eyed, hair blowing wildly, bouncing across the surface like a skipping stone. If kids from school saw her, they’d probably think she’d lost her mind.

Which isn’t far from the truth.

Ahead, a wave sweeps toward her, getting bigger until it looms like a mountain and begins to wobble. The wave must be at least fifteen feet. She tenses as the white crest crumbles and turns into an avalanche of water.

A jolt of panic courses through her—​if the wave hits her, she’ll be crushed. She instinctively jams the engine hard over to dodge the onslaught and eyes the angle of the swell, the push of the wind, and the speed of the dinghy. She might make the shoulder of the wave. The far edge hasn’t broken yet. If she can get there in time, she can get up and over before the wave reaches her.

She twists the throttle harder, knowing that the engine is already maxed out. But every bit of power matters now as the boat begins to rise up the wall of water. She keeps the side of the boat to the wind, using the surface like a sail to gain any extra distance.

It doesn’t help. The boat loses speed as it rises up the wave, and Mia realizes that this could be the end, the roar of the wave growing louder, only seconds away now. And, for the first time since leaving Duluth, Mia screams in fury, letting all the anger and fear boil out. She stands precariously and rages against everything with a primal, wild war cry—​a warning to the wave, to the sea, to the world—​hat she’s not giving up.

And then the wave hits her.

Chapter 2
Two Weeks Earlier

A light wind ripples the perfect blue of the Caribbean. In every direction, the water is flat and calm. Mia glances up at the tels on the sail of her forty​­three­foot sailboat. The little snippets of nylon flutter loosely. Barely enough wind to make headway. Mia estimates they’re moving at two knots bearing south by southwest. She squints over the bow. The sky is dotted with dollops of white clouds. On the foredeck, the dinghy is lashed upside down, looking like a baby napping on its mother’s chest. Everything is quiet and almost pleasant.


Kaden doesn’t even notice the soft breeze ruffle the pages of his plastic-­wrapped copy of Captain Underpants. He’s gotten so used to the boat, it’s like he doesn’t remember their life before. It’s easier for a ten-​­year-​old, Mia thinks. Her little brother has pretty much forgotten Duluth.

It’d be cold there today, she thinks. March in Minnesota meant parkas, scarves, and breath billowing like smoke. If she were home, she’d be doing her best to fit in: wear the right clothes, say the right things, or at least not say the wrong things. With green eyes and a wide, angular jaw, she is strikingly pretty, but she tends to say weird things about engines and radio waves. With other kids in Duluth, she had a blazing intensity that left little room for small talk. People at school thought she was odd and kept their distance.

It hurt and made her wonder if she just wasn’t cut out for high school. Maybe she deserved to be where she was now, piloting a battered sailboat in the Caribbean instead of attending her junior year back home.

A gust of wind hits them and heels the boat over. The thing is nearly an antique, a ­forty-​­three-​­foot sloop built in the ’70s. It’s about the same size as a yellow school bus and it used to freak her out when the boat rolled with the wind. It felt like they were going to tip over. Now, she leans automatically as the boat rolls. She keeps her hands on the wheel, the gust whistling through the shrouds, and after a moment, the boat slowly lumbers back up.

Her overalls have long since been pushed to the bottom of the cabinet in her berth. Carhartts feel like ­thirty-​­six-​­grit sandpaper on your skin when they’re soaked with salt water. In their place, she’s got on her Caribbean uniform: a threadbare black sports bra, blue polyester shorts, and cheap sunglasses that are so scratched, it’s like looking out of a cloud.

If only Sadie were here, things would be better. She’d be like, What the hell are you wearing? and then tell her exactly what to do and say. Sadie always knew what to do.

Sadie. That is the hardest part, being away from her best friend. Her only friend, actually. She can picture what they’d be doing right now. They’d be on opposite sides of some class with their laptops open. The school gave each kid a computer and said they were empowering the students to make good decisions. Nobody did. Their favorite game was to start a video chat in the middle of class. They turned the sound off and took turns making their faces ugly with filters. Whoever laughed first lost, and usually got busted by the teacher.

Overhead, a cloud passes across the sun, darkening the sea, and Mia feels a tightness in her chest. If she could just talk to her friend, maybe they could work things out. Instead, it’s been nothing but silence since The Incident.

The memories of that day start to crash through her mind like a demolition derby. The school cafeteria. The splat of yogurt and then chicken potpie as Mia hurled them against the wall. She couldn’t even hear herself screaming, she was so angry.

The flapping of the tels on the sail brings her attention back to the boat. The wind has picked up. Mia cranks the mainsail winch, bringing the boom in. Her forearms and biceps are thicker now—​she can see the muscles ripple as she turns the crank. She smiles at the thought of what Sadie would say. She’d call her a brute.

Mia spins the wheel lock, holding their position, and moves past Kaden to an array of silvery glass squares strapped onto the starboard railing. She unclips the boat’s old handheld radio—​a waterproof walkie­talkie for calling nearby ships—​and detaches the back.

For months now she has been completely isolated and cut off. Her cell phone is stuffed away in her cabin because there’s no cell network out here and the radio’s battery is dying. The thing can barely reach nearby boats.

But she hasn’t given up hope. If she can keep the dying battery powered up and dial in the right frequency, it might be able to connect with one of the eighteen amateur radio satellites orbiting the earth and patch her through to Sadie’s cell phone.

Mia connects an alligator cable to the glass squares and uses a multimeter to measure the current. The glass squares are an improvised portable solar panel she built herself. She could plug in to the onboard power, but she doesn’t want to be tied to the suffocating boat. She wants to be able to go ashore—​even if it’s a deserted ­island—​­and call her friend in private. There’s no privacy on a boat.

“Gotta be the electrodes,” she mumbles, noting that the wattage is still too low.

Kaden looks up but he’s gotten used to her talking to herself and goes back to his book without saying anything.

“It’s not the electrodes,” Lene says. She’s sitting cross-​legged above the hatchway that leads below deck and is wearing her usual beige turtleneck and baggy, pea-​green suit jacket. It’s a ridiculous thing to wear on a boat, particularly in the muggy Caribbean, but Lene doesn’t care, in part because she’s a world­renowned physicist. Also, because she is Mia’s imaginary friend. The real Lene Hau at Harvard has no idea that Mia exists.

“You should try a different substrate,” Lene says helpfully. “Because what you’re doing now really isn’t working.”

“I know, Lee,” Mia mutters. The correct way to pronounce Lene’s name is “Lee-nah,” but when Mia gets frustrated with her friend, she sometimes says just the first part.

Kaden looks up again. He can’t see Lene so Mia’s strange mutterings can sometimes confuse him. Mia ignores him and stays focused on her homemade solar panel. It’s made of five glass squares and each one represents a different idea about how to maximize electrical production using naturally occurring things. One is made out of wild berries, another from harder‑to‑get titanium dioxide.

She’s been at it for months now, slowly improving the power generation. When they’re anchored, she spends her days shuffling around the boat’s small kitchen, boiling concoctions and mumbling with her imaginary friend. Eventually, she’ll have a completely mobile communication system, the castaway geek version of a cell phone.

“This is one of the rare things your mom and I see eye to eye on,” Lene says. “You’re definitely becoming a weirdo.”

Mia wants to argue but realizes it would only confirm the point. After all, if your imaginary friend and your mom agree that you’re weird, you probably have a problem.

Mia feels a pang of tension just thinking about her mom. Her dad’s soft snoring has driven her mom out of the forward cabin and Mia can hear her tossing fitfully on the banquette below. They had a long passage last night and Izzy left Mia in charge so she could sleep. These moments on deck without her parents are one of the few times she can relax.

Normally, her mom is badgering her to read a book or study for an AP test, which is ironic because Izzy pulled them out of school to do something called “unschooling.” Izzy had read about it in a book and it basically means they can do whatever they want. The book said that unschooled kids start by goofing off until they get so crushingly bored, they decide that studying sounds great. The approach was supposed to help a student discover “inner motivation” via intense boredom. But, after six months, Mia is still goofing off, at least as far as her mom is concerned.

Mia nibbles a stray piece of skin on her index finger and winces when it comes off. The sharp, fleeting pain is a distraction from the sound of her parents below. She can hear every snort, burp, and fart. Reason 147 why this was a bad idea: You never want to be jammed in this close with your parents.

They were in their kitchen eating breakfast in Duluth six months ago when her mom said she had some news. Kaden barely paid attention, more interested in his Frosted Mini-​Wheats. Ethan, her dad, was fidgeting uneasily with the kitchen faucet, which had a slow leak. It was a week after The Incident.

Mia knew something was brewing because her mom had been scrubbing the counters incessantly, staying up after everyone went to sleep. Her mom was obsessed with cleanliness but this was worse: The laminate countertops were rubbed through to the particleboard underneath.

Mia figured her parents were getting divorced. Everything seemed to be falling apart. Mia had essentially been expelled. They asked her to “seek an educational setting more supportive of her mental health.” At the same time, her mom was going to pieces, washing her hands till they were cracked and raw. She vacuumed their stained carpeting nonstop and yelled at the landlord, who refused to replace it. She’d gotten fired from her waitressing job at a steak house. It wasn’t good when the waitress’s hands looked like raw meat. Her mom always had trouble with what she called “goddamn germs,” but this was something else. She needed psychiatric help.

Instead, she announced that they were going sailing.

There was a hush in the kitchen. The fluorescent lights hummed.

“Like for the day?” Mia asked.

“Longer.”

Mia looked back and forth between her parents. For years, her dad had been refurbishing a broken forty-​three-foot sailboat named Graceland in the parking lot of their apartment building. The boat was a never-ending argument. Any time her dad got carpentry work, he put the money into buying engine parts or new winches. It was like he had a mistress and it made her mom furious: She pointed out that there were a million other things they could do with the money while the damn boat just sat there, taking up their two parking spots.

So it was surprising to hear her mom talk about actually sailing somewhere.

“We’re getting rid of everything, and we’re going to sail to the Caribbean,” her mom said, the words coming out in a rush. Mia was stunned. It seemed like her mom was drinking. When she’d had a few glasses of wine, she liked to talk about how much better life was anywhere other than Duluth.

“So you want to go sailing for the summer?” Mia asked, trying to understand.

“No,” her dad said. “We’re not coming back.”