Chapter One ONE
Puerto Villamil

Isla Isabela

The Galápagos Islands, Ecuador

Present day

A hammerhead shark slid through the water beneath Charlie Thorne.

Charlie watched it glide below her feet as her surfboard bobbed in the ocean. It was a big shark, about nine feet long, capable of doing some serious damage. But Charlie’s reaction upon seeing it was excitement, rather than fear. Charlie had seen plenty of hammerheads while surfing in Puerto Villamil. Despite their threatening appearance, statistically, she had little reason for alarm as long as she didn’t do anything stupid around them—and Charlie Thorne was as far from stupid as you could get.

Even though she was only twelve, Charlie had an IQ that rivaled that of anyone who had ever lived. In a situation like this, she couldn’t help but analyze the numbers. She knew that out of the billions of people on earth, fewer than twenty died each year from shark attacks; far more humans were killed annually by falling coconuts. But then, few people actively went surfing in shark-infested waters, where the chances of getting attacked were much greater. Most shark attacks were thought to be mistakes; from underneath, a human on a surfboard had a silhouette similar to that of a sea lion, the preferred food of many sharks. So Charlie was always careful; she didn’t surf while she was bleeding, or wear shiny jewelry that a shark might mistake for the flash of fish scales, or thrash around in the water like a wounded animal. Now, watching the hammerhead, she stayed calm and still.

The shark didn’t seem to care about her at all. It certainly knew she was there, but it continued onward as though the thought of consuming her had never even entered its mind. It was paralleling the coastline of Isla Isabela, heading toward a rocky outcropping where the sea lion rookeries were. Why sharks would pass up an easy meal like a human in favor of harder-to-catch prey like a sea lion was unexplained, but most scientists presumed that sharks simply thought humans didn’t taste very good.

Another hammerhead passed beneath Charlie, and another after that. They were both smaller than the first, but not by much.

This didn’t surprise Charlie: Hammerheads often swam in schools, sometimes numbering up to a hundred. She turned on her board to look behind her. Sure enough, more sharks were coming, their large dorsal fins poking above the surface.

Charlie figured it was time to get out of the water. The odds of an accidental attack were rising by the second.

Fortunately, a good-size wave was coming her way, a bulge in the ocean building as it approached the shore. Charlie watched it—and the numbers came to her.

They simply appeared in her mind, as usual: instant calculations of the speed of the wave, the most likely cresting point, and how fast she would need to paddle to put herself there. Puerto Villamil wasn’t home to many other surfers—or many other people, period—but Charlie had already become legendary among the few who lived there. Even surfers with decades of experience mistimed a wave on occasion, but Charlie never did. Somehow, she was always exactly where she needed to be.

Whenever anyone tried to talk to Charlie about how she read the waves so well, she dodged the question. “Tuve suerte” was all she would say. “I was lucky.”

The others surfers knew that no one could be that lucky, but Charlie wouldn’t say anything else. Charlie had barely spoken to anyone in Puerto Villamil since arriving four weeks earlier. No one knew where she was from or why she had come to such a far-flung place—and they certainly didn’t know her age. Since Charlie looked and behaved much older than her years, everyone assumed she was at least eighteen. The only information she had volunteered was that her name was “Mariposa Espina,” which wasn’t true.

Charlie could pass herself off as a native of almost any place on earth, because ethnically, she was a mix of different races—although she didn’t look like one more than any other. Plus, she spoke over a dozen languages and could understand many more. In a single day, while en route to the Galápagos, she had told different people that she was Thai, Greek, Kenyan, Guatemalan, and aboriginal Australian, and no one had questioned her at all.

Fewer than two thousand people lived in Puerto Villamil, so the arrival of one more was of interest to the locals. There were many rumors as to who Charlie really was and why she had ended up there. Many of them were bizarre and outlandish. Although none were anywhere near as bizarre and outlandish as the truth.

Now Charlie lay flat on the board and paddled with her arms, taking care to do so with smooth, strong strokes that wouldn’t startle the hammerheads below her. She headed directly to the spot where she had calculated the wave would break. Sure enough, the swell rose behind her, exactly as she had predicted, and grew into a ten-foot wall of water. Charlie quickly leapt to her feet upon the board, caught the front slope of the wave, and expertly rode down it. As the wave broke, she surfed right through the curl. She stayed upright all the way to shore, even as the wave collapsed upon itself behind her, then slid into the shallow water and calmly stepped off the board and onto the beach as casually as though she were stepping off a bus onto the curb.

The locals gathered on the shore watched with amazement. Charlie had been a novice surfer when she had arrived in Puerto Villamil. Even though she had been able to spot where the waves would break, she hadn’t been able to ride them. But within a few weeks, using her natural athleticism and her unnatural skill at reading the waves, she was surfing better than most people could after years of practice. The people watching her now shook their heads and uttered the name they all called her behind her back. “Perfecta.”

It was warm on the beach, as usual. Since Isla Isabela sat directly on the equator, the temperature didn’t vary much. Charlie peeled off the neoprene suit she had used to stay warm in the water, revealing the bathing suit she wore underneath, then picked up her board and started home barefoot through town.

There wasn’t much to Puerto Villamil, which made sense, given that it was one of the most remote towns on earth. It sat on the southern fringe of Isla Isabela in the Galápagos Islands, which were well off the coast of mainland South America. Isla Isabela was actually the largest of the Galápagos, but most of it was uninhabitable, as it was quite volcanic and almost devoid of fresh water. The Sierra Negra volcano constituted much of the island; its crater was the second largest on earth, after Ngorongoro in Africa.

Therefore Puerto Villamil, set at the base of Sierra Negra, was about as far from civilization as one could get. Should a riptide have snapped Charlie away from shore, it was nearly nine thousand miles until she’d see land again. For this reason, it sometimes felt as though the little town was on the very edge of the earth.

That was one of the reasons that Charlie had chosen to come here. She wanted isolation. She wanted to be as far from other people as possible. It was safer that way.

There were more marine iguanas in Puerto Villamil than people. The lizards were quite large, growing up to five feet long, and they were everywhere: lazing on the beach, walking along the dusty streets, lounging on porches, and wandering into the stores. They were just as fearless of humans as they had been back when Charles Darwin had arrived, as was the case with most of the wildlife in the Galápagos. Animals often needed a long time to evolve a healthy fear of humans—and here, there hadn’t been enough. As Charlie headed through town, two sea lions were sleeping directly in the middle of the street, while three penguins waddled toward the small marina. Many people were surprised to learn there were penguins in the Galápagos, as opposed to Antarctica, but this species was endemic to the islands. It was endangered, with only 1,500 left, although they were relatively common on Isla Isabela. One of the things that Charlie liked the best about the Galápagos, in addition to its remoteness, was that it was the only place on earth where you could snorkel with an iguana, a sea lion, and a penguin all at once.

The roar of outboard motors suddenly cut through the town. They were loud enough to startle the penguins, which scurried away frantically, although the sea lions continued snoring loudly. Charlie paused in the street and looked back toward the dock at the eastern edge of Puerto Villamil.

A speedboat had rounded the southern tip of the island and was headed toward town. It was big for a speedboat, with two enormous engines attached to the stern, and it skimmed across the water like a skipped stone.

In the four weeks that Charlie had been in Puerto Villamil, she had never seen a boat like this. Every day, a few boats bringing ecotourists would arrive, but those were all small cruise ships, built for comfort rather than speed. Some of the local fishermen had boats as well, but those were all old, battered, and weather-beaten. This boat was very different; It was expensive and built to go at very high speeds, the sort of craft you’d see millionaires racing along the coast in Miami or the Côte D’Azur in France.

That didn’t necessarily mean anything was wrong, but Charlie was always on the lookout for things that were out of the ordinary. When you lived your life on the run, you had to stay attuned to your surroundings at all times.

Charlie resumed walking toward her home. She didn’t run, because that would draw attention. But she did pick up her pace, striding briskly through the town.

The house Charlie rented was small and ramshackle—there really wasn’t anything big or well built in Puerto Villamil—but she didn’t need much. It sat beside the marsh that marked the western boundary of town. Just behind the house, a path snaked through the wetlands to the Tupiza Tortoise Breeding Center, where Charlie volunteered her time, helping to keep the celebrated Galápagos tortoises from going extinct.

A woman she had never met before was on her porch.

Charlie noticed her from two blocks away. It wasn’t hard, as the woman apparently wanted to be seen. She was sitting in the rocking chair on the porch, reading a book.

She wasn’t from Puerto Villamil. Charlie could recognize every one of the town’s residents. The woman had unusually slim features: her face, nose, and lips were all narrow lines, although her eyes were wide and round. She reminded Charlie of a Modigliani sculpture. She was dressed in the same outfit that the volunteers at Tupiza wore: khaki shirt and shorts, although instead of dusty, thick-soled work boots, she wore running shoes. Despite the workmanlike clothing, she was strikingly beautiful.

A visitor was also an unusual occurrence; Charlie had never had one since arriving in Puerto Villamil. None of her friends or family knew she was here—and ideally, her enemies didn’t either. Combined with the arrival of the speedboat, the visitor’s presence set Charlie’s brain humming, analyzing the probabilities of all that was happening. She didn’t like what she came up with.

Still, Charlie didn’t run. She had nowhere to run to. And the woman didn’t seem to be a threat. Threatening people tended to ambush you. They didn’t sit on your front porch in broad daylight.

As Charlie got closer, she noticed that the woman was wearing makeup. Not much, just a bit of eyeshadow and lipstick, but most people around here didn’t bother with makeup at all. The woman had also spent time doing her hair, and her clothes were spotless and expertly pressed. All of it indicated that this was a woman who cared about how she presented herself.

She looked up as Charlie approached, dog-eared a page of her book, and smiled pleasantly. “Hello, Mariposa. My name is Esmerelda Castle.” There was a slight accent to her words, as if English was not her first language.

Charlie’s immediate response was to pretend as though she couldn’t speak English at all. Any time a tourist had approached her over the past few weeks, she had quickly said “No hablo inglés” and walked away. But Esmerelda seemed very well aware that Charlie understood English, so Charlie figured there was no point in acting like she didn’t. “Hi,” she said, propping her surfboard against the wall of her house.

“I work at the Darwin Research Station on Isla Santa Cruz,” Esmerelda said. “We’ve found something of great interest there, and my friends at Tupiza suggested you might be able to help us with it.”

“Who at Tupiza?” Charlie asked suspiciously.

Esmerelda smiled again, as though she found Charlie’s suspicions amusing. “Everyone, really. Raoul Cabazon. Stacy Devillers. Arturo and Fred and Johnny. They all say that you have a gift for codes and puzzles and that sort of thing.”

Charlie nodded. There didn’t seem to be any point in denying this. The names Esmerelda had mentioned were all people who worked at Tupiza, and Charlie often solved puzzles during her breaks there. Crosswords, cryptics, acrostics, and that sort of thing. She was addicted to them. And what Esmerelda was talking about struck her as strange but intriguing. “You found a puzzle at the research station?”

“Yes. A code of some sort, we believe. It was etched into the shell of a tortoise.”

Charlie’s eyes widened in surprise. “Who would etch a code into the shell of a tortoise?”

“That’s where this gets really interesting,” Esmerelda replied. “It appears the code was left by Charles Darwin himself. And we could use your help figuring it out.”