Contents

      Acknowledgment

      Chapter 1

      Chapter 2

      Chapter 3

      Chapter 4

      Chapter 5

      Chapter 6

      Chapter 7

      Chapter 8

      Chapter 9

      Chapter 10

      Chapter 11

      Chapter 12

      Chapter 13

      Chapter 14

      Chapter 15

      Chapter 16

      Chapter 17

      Chapter 18

      Chapter 19

      Chapter 20

      Chapter 21

      Chapter 22

      Chapter 23

      Chapter 24

      Chapter 25

      Acknowledgment

      Thanks to my great MIRA Books team.

       I value your expertise and support:

      Miranda Stecyk

       Margaret O’Neill Marbury

       Dianne Moggy

       Donna Hayes

       Craig Swinwood

       Katherine Orr, Marleah Stout

       and their great staff,

       including Maureen Stead

       and especially all the dynamic MIRA Books

       sales staff!

       And, as ever, to my greatest supporter, Don.

      1

      The Gulf of Mexico off South Florida

       September 12, 2006

      When Briana Devon surfaced, her boat was gone. Something—besides the fact that the gulf had gone rough since she’d begun her dive—was terribly wrong.

      She struggled to keep her underwater camera and strobe from being ripped away by the waves. Her tethered plastic slate with its latex rubber pencil she used to make notes underwater smacked her face; she thrust it behind her.

      She kept the regulator in her mouth, clenched between her teeth. Still sucking in the air from her tank, she heard the hiss of her more rapid breathing mingled with the howl of the increasing wind. Since she was fairly low on air, her single tank yanked back and forth on her BC, the vest-style buoyancy compensator that supported her in the water.

      This was impossible! Had she come up in the wrong place? No, the pelican float she’d deployed bobbed wildly, riding the waves. She was where she meant to be, but where was Daria and their dive boat? And how fast the distant storm had come up.

      Holding on to her gear and using her flippers, she spun in a circle. Maybe the Mermaids II was just blurred by the darkening horizon. No, all she saw were clumps of clouds, not even other boats, with that storm coming in much faster than the weather-man had predicted. But Daria would never have left her out here.

      Despite being a veteran diver, panic pulsed through Briana for herself and her sister. Bree and Daria Devon were not only twin sisters but had been best friends since they could remember.

      Bree put more air in her BC to keep afloat and fought to calm herself. After all, she’d been diving for twenty of her twenty-eight years and swimming these waters even longer. Every week, she and Daria dived the artificial reef made by the wreck of an old trading boat to check on the growth of pollutant-endangered sea grass and marine life. The grass was a bellwether for the health of the gulf waters in general. It had all been routine until now.

      Bree had not noticed whether the anchor had been pulled up. She’d only been intent on doing her work well and quickly. Just take the photos, make the notes, get proof. The results were bad news that was going to upset a lot of powerful people. She’d only come up early because visibility was lessening, and that meant the waves were kicking up. But she’d never imagined this churning, gray sea and gathering storm.

      The twins had always buddy-dived unless they were just scraping barnacles off hulls at the marina, but there were two reasons Daria hadn’t made the dive with her today. She’d suddenly developed a bad toothache, which would have made the underwater pressure excruciating for her. And someone had to stay with their dive boat: Daria had given Manny, their only employee at their search-and-salvage shop, the afternoon off since he’d been having so much trouble with his daughter. Actually, Daria hadn’t been diving much this past month anyway, since she’d been so busy concentrating on her accounting class.

      Bree’s arms ached from trying to hang on to her camera and strobe in the increasing turbulence. She had never feared this vast stretch of water, only respected it, but now terror immobilized her. Alone. Abandoned? She should probably start swimming in, but she was over four miles out and she’d have to ditch her precious gear. She should have taken it as a bad sign when she saw that bull shark cruising past the reef instead of the usual resident grouper. Bulls became disturbed whenever the water was riled, and they were known to attack humans. How many times had she warned someone not to swim alone or far from shore, and to avoid splashing?

      Bree had a whistle to summon help, but there was no one in range to hear it. She could set off her strobe to try to attract attention, but holding it above the waves would wear her out. Reluctantly she let her strobe lights and camera drop, hoping they would snag somewhere near the wreck and she—they—could retrieve them later. The camera was worth big bucks; they’d scraped a lot of barnacles off yachts to buy it.

      The twins’ co-owned marine search-and-salvage shop had been struggling, but things were on the upswing lately. They did everything from underwater surveys to hull maintenance to retrieval of lost items or sunken vessels. It could be dirty, hard, even dangerous work, but they both loved it. They knew what was below the surface of the gulf off southwest Florida almost as well as they knew each other.

      It had been a surprise and a thrill when the prestigious Clear the Gulf Commission had hired them—not their larger rival across the bay—to record the difficult comeback of off-the-coast marine life under siege from toxic runoff. The whole local ecosystem was being poisoned by fertilizers from sugarcane fields, golf course fairways, and polluted water releases from just too many people.

      To save her strength, Bree decided to dive again and get as far as she could underwater before she’d have to ditch her tanks and weight belt to swim in. Though she saw no watercraft, perhaps one would be heading for safe harbor and she could hail it. She upended and kicked down until the turbulence seemed to lessen.

      The Gulf of Mexico, off Naples, Marco Island and Turtle Bay, was a shallow body of water, at least compared to the Atlantic. The bottom was fairly flat for a long way out: after an initial drop-off, it deepened about two feet per mile and was broken only by small ledges and man-made reefs. But because the depth was fairly shallow, the gulf could get violent fast. It was the underwater storm of sand and silt that had tipped her off to the one above. Though she did a lot of close-up, well-lit macrophotography, even that was looking grainy today.

      Most people—especially tourist divers from “the frozen North,” as their dive friends called it—thought the water off Naples was not great dive territory. But the twins had always loved it more than the glamour spots of the Keys or even the Caribbean. Fifteen feet of visibility in this part of the world was a great disappointment