“That looks like fun,” Benny said, watching as Melanie smoothly guided the rowboat through the water.

  “You certainly did a good job on the wind-surfing simulator,” Jessie said. “Grandfather will be proud of you. We’ll be seeing him tomorrow, you know.”

  “Tomorrow?”

  “We’ve been here a whole week,” Violet reminded him. “The time went fast because we’ve been doing so much.”

  “And learning so many new things,” Soo Lee added.

  “I wish we could stay longer,” Benny said. “I never got to use the real wind-surfer. The kind that goes in the water.”

  Violet put her arm around him. “Maybe next time, Benny.”

  After dinner, everyone sang songs and toasted marshmallows around a campfire. Soo Lee had never tasted marshmallows before, and Benny showed her how to thread them on a stick and hold them over the flames.

  “Mmmm!” she said when she’d tried her first toasted marshmallow. “This is great!” Violet felt a little sad because she knew she would miss the camp, and especially Melanie, who had become a good friend. And worst of all, they had never solved the mystery of the missing coral!

  “Are you thinking the same thing I am?” Jessie said quietly. She had caught the look on her sister’s face as she stared into the fire.

  Violet nodded. “Probably. I’ve been thinking about the coral thief—who he is, what he’s planning to do next. This is the first time we’ve come up against a mystery we couldn’t solve.”

  Jessie sighed. “I know. All we can do is hope that the thief slips up somehow, and Melanie catches him after we leave.”

  A little later, the counselors suggested a hike around the island, but the Aldens decided to stay at the campfire. The sun had already set in a blaze of fiery orange, and the night air was soft and balmy.

  “It’s so peaceful here,” Jessie said. “I wantto sit and watch the stars come out one by one.”

  “I want to watch the moonlight,” Violet said. “It looks so pretty when it shines on the water.”

  “And I want to watch the campfire,” Benny said. “We still have another whole package of marshmallows left!”

  Everyone laughed, and the group began hiking along the shore, leaving the Aldens alone.

  Darkness spread across the island very quickly, and half an hour later, Benny was startled to see a flashing light on the water. It was at the far end of the island, but he could see it clearly, twinkling in the distance. He stood up, curious, and then he heard a familiar sound. Putt-putt. Putt-putt.

  “There’s that boat again,” Violet said in a hushed voice. “I know it!”

  Henry and the girls scrambled to their feet. “How can you be so sure?” Henry asked.

  “Because it’s the same boat we heard a couple of nights ago,” she insisted.

  “Don’t all powerboats sound alike?” Henry asked.

  “This one’s different,” Violet said, shaking her head. “It skips a putt every now and then. I know it’s the same one we heard before. Boat number six.”

  “You’re right,” Henry agreed. “Melanie said that the boat has a bad transmission, and that’s why it skips every so often.”

  “What can we do?” Jessie asked eagerly.

  Suddenly the putt-putt sound stopped, and the Aldens stood motionless, straining to hear.

  “Why has the noise stopped?” Benny whispered.

  “I don’t know—” Violet started to say, and then stopped. All at once she realized what was going on. “Oh, no!” she cried. “The thief has docked the boat. What if he’s going to steal more coral?”

  “We have to get Melanie and the other counselors,” Henry said. “And we need to move fast.”

  “They’ve been gone for a while,” Jessie said. “How will we find them?”

  “We’ll have to split up,” Henry said. “Violet, you and I will take the rowboat to the other end of the island. At least we’ll know what’s going on, and we may even get a look at the thief.”

  “Soo Lee and I can try to find the campers,” Jessie said.

  “Don’t walk along the shoreline. It will take too long,” Henry pointed out.

  “We’ll cut through the woods instead,” Soo Lee said quickly. She scrambled to her feet, glad that she had worn long pants and sturdy shoes.

  “Hey,” Benny said. “How about me?”

  “You’re coming with us,” Henry said, grabbing his hand.

  “Good—there are three life jackets inside,” Violet said when they reached the rowboat a couple of minutes later. They quickly put them on, and Henry helped Violet and Benny into the rear seat. Then he lowered himself into the middle seat and took up the oars.

  When they had almost reached the shore at the other end of the island, Benny heard a sharp sound. “What’s that?” he asked.

  “I bet the thief is using a hammer on the coral bed,” Henry said in disgust. “We’ll have to hurry.”

  They docked the rowboat as quietly as they could and crept cautiously along the hard-packed sand. The beach was very dark, but suddenly they saw a light dancing at the edge of the water, just a few yards away.

  “That light’s moving all by itself!” Benny said in a shaky voice.

  “No, there’s a person holding it,” Violet said. She grabbed Benny’s hand and held it tightly. “Someone’s coming out of the water and he’s all dressed in black. That’s why you can’t see him.”

  “He’s wearing a wetsuit,” Henry whispered. They inched a little closer. Violet noticed that the person was slim, and carrying a big chunk of coral. A snorkel mask covered most of his face.

  “Who is it?” Benny asked, edging close to Violet.

  She shook her head. “I can’t tell yet. Let’s see what he does.”

  They watched as the dark figure lifted the coral into a powerboat docked nearby and went back into the water.

  “He’s after more coral!” Violet said angrily. “We have to stop him!”

  “I know,” Henry said, “but we need help. Can you stay here and try to get a look at his face? I’m going to take the rowboat and find the others.”

  “Be quick,” Benny said.

  “Don’t worry, I will,” Henry assured them.

  He darted back to the rowboat, just as the thief emerged from the water. After dropping another load of coral in the powerboat, the figure in the wet suit stopped to rest for a moment.

  “What’s he doing now?” Benny whispered.

  “I don’t know—” Violet started to say, and then stopped. The figure had pulled off his snorkel mask, and Violet nearly gasped in surprise. It was Katherine Kelly!

  She started to inch backward, still clutching Benny by the hand, when he gave a sharp yelp of pain.

  “Oh, Benny,” Violet said. She didn’t want Katherine to see them.

  “I’m sorry,” he said in a little voice. “I stepped on a shell.”

  Katherine’s head swung around at the sound, but before she could spot them, Violet ran into the woods and pulled Benny behind a giant banyan tree.

  Suddenly an arm appeared out of the darkness. It grabbed Violet by the shoulder and she almost screamed.

  “It’s okay,” a calm voice said. “It’s only me.” When the man stepped closer, she recognized his face.

  “Nick Simon?” she asked doubtfully.What was he doing in the woods at night?

  “There’s nothing to be afraid of,” Nick said. Violet wasn’t sure if she could believe him.

  “What’s going on?” Henry’s voice boomed out.

  “We’re over here!” Violet called out. Her brother was at her side in a second.

  “I was just stepping into the boat when I heard Benny cry out,” Henry said. Then he looked at Nick. “What are you doing here?”

  “I’m here for the same reason you are. To catch the coral thief.”

  Henry hesitated. Was Nick telling the truth? Up until now, he had been one of the main suspects.

  “He’s not the thief!” Benny blurted out. “It’s Katherine Kelly. We saw her!”

  “Where is she?” Nick asked.

  “She’s down at the beach,” Violet said.

  “That’s all I need to know,” Nick said. He took a walkie-talkie out of his pocket andspoke a few words. When he finished talking, he smiled at the children. “They’ll pick her up in a few minutes. We have officers all over the island.”

  “Officers?” Jessie said in surprise. “You’re with the police?”

  “Detective Nick Simon,” he answered, pulling out his badge. “I’ve been working undercover for months, trying to get a lead on the thief. But you’re the ones who really solved the crime,” he told them. “I knew it was someone at Camp Coral, but I couldn’t figure out who.”

  “Neither could we,” Henry said. “We even suspected you.”

  “Are you sure the police will get there in time?” Violet said worriedly. “All she has to do is jump in the powerboat and get away.”

  “Not without this, she won’t.” Henry held up a thin wire. “She can’t get far with her spark plugs disconnected.”

  Nick laughed. “You’d make good detectives.”

  CHAPTER 10

  The Mystery Is Solved!

  “That about wraps it up, Nick,” a pale man with sandy hair said a few minutes later. He was standing at the edge of the shore, watching as another officer handcuffed Katherine Kelly, and helped her into a police patrol boat.

  “I know you!” Benny said. “I met you with Nick in Key West. He said you were a fisherman.”

  Nick laughed. “This is Officer Adams, Benny. I’m afraid I had to tell a little white lie. I couldn’t explain that we’re both undercover investigators.”

  “What’s going to happen now?” Henry asked. He glanced at Katherine Kelly, who glared back at him.

  “It’s an airtight case.” Officer Adams pointed to a group of men in Coast Guard uniforms who were carefully placing the stolen coral in clear plastic bags. “We’ve got eyewitnesses, we’ve got the stolen coral, and we’ve got the tools she used.”

  “It sounds like you caught her in the act,” Nick said.

  Officer Adams nodded. “We did. She had just dumped another load in her boat. It’s funny, but she couldn’t get the engine started. That was a lucky break for us.”

  Nick laughed as Henry held up the wire. “It was more than just a lucky break. Henry disconnected her spark plugs. She’d be miles away by now, without the help of my young friends.”

  Jessie and Soo Lee appeared just then, followed by a group of counselors and campers.

  “What’s going on?” Jessie asked, and then gasped as she spotted Katherine Kelly in handcuffs. “She was the one?” she whispered.

  “That’s right,” Benny said excitedly. “We caught her stealing the coral and we recognized her when she took her face mask off. And then—we had to run into the woods! It was scary!”

  “I’m glad you’re okay,” Jessie said, giving him a quick hug.

  “Someone better fill me in,” Melanie said, coming up behind Jessie. She was out of breath. “We heard the noise and ran all the way back from the other side of the island.”

  Nick smiled. “Well, the bottom line is that the kids solved the crime for us. Without them, Katherine might have made one last haul, and then disappeared for good.”

  “But I don’t understand,” Jessie said. Sheturned to Nick. “You’re not really a marine biologist?”

  Violet laughed. “He’s a police officer, but it’s a long story.”

  “I have a lot of questions, too,” Melanie said. “How about if we all go back to Camp Coral and discuss it?”

  Half an hour later, everyone met at the picnic tables down by the dock at the camp. The other officers had left the island, but Nick stayed behind to talk about the case. Melanie lit some tiki lamps, and the campers and counselors gathered close to ask questions.

  “Was she really an underwater photographer?” Soo Lee asked.

  “Yes, she was a real photographer. Her work has been featured in some big magazines.” Nick paused. “I guess she just decided she could make more money from stealing coral.”

  “It was the picture! That’s what made me wonder!” Violet blurted out. Everyone turned to look at her. “Katherine took a really pretty picture of a sunset and we saw it hanging to dry in the darkroom.”

  “I remember how much that picture bothered you,” Jessie said. “But I never understood why.”

  “I didn’t either—until now.” She turned to Melanie. “There was something about the rock, and the sunset that looked so familiar. I realized that I had seen that exact same view before—from your private island!”

  “So the only way Katherine could have gotten that picture was if she had been standing in the same spot we were,” Jessie said slowly. “She probably discovered the big coral bed that day and decided to chop away at it.”

  “It will take hundreds of years to grow back,” Melanie said sadly.

  “Don’t feel bad, Melanie,” Violet said, edging close to her. “At least she’ll never be able to do it again.”

  “When did you first suspect her?” A male voice came from the back of the crowd.Henry turned to see Joshua Slade raising his hand.

  “Right from the start,” Nick answered. “But I suspected a lot of people. You and your wife, for example.”

  Hilary Slade laughed nervously. “Surely you didn’t suspect us.”

  “I certainly did. You two don’t know much about sailing for a couple who are supposed to run a charter business.”

  “That’s right!” Soo Lee agreed. “You didn’t even recognize a square knot when I showed you my macrame piece.”

  “And you stuffed a fish inside your shirt!” Benny piped up. “I saw you that night we were out collecting specimens.”

  “I stuffed a what? Oh, now I get it.” Joshua laughed. “That wasn’t a fish. I thought I saw a rare coin in the water, and I scooped it up and hid it in my shirt. I didn’t think anyone saw me.”

  “You’re interested in rare coins?” Henry said. “So that was you snooping around our cabin that night!”

  Joshua looked embarrassed. “I’m afraid it was. To tell the truth, we’re treasure hunters, not sailors.

  “From the way he talked, I thought Benny had found a doubloon. I didn’t realize it was worthless.” He paused. “The only valuable thing I found here was the conch shell and it was cracked.”

  “You took my conch shell?” Violet asked. Joshua looked embarrassed, realizing his slip. “I wanted to show it to one of my investors. I wasn’t sure how rare it really was.”

  “What did you do with it?” Melanie asked.

  “I stuffed it in a drawer in the classroom,” Joshua said defiantly. “I figured you’d find it eventually.”

  Everyone was silent for a moment, and then Jessie spoke up. “We even suspected you, Nick. Someone took a powerboat out one night, and we found a key ring with the initials NS lying on the seat.”

  “I can explain that,” Nick said. “NS stands for North Star. They’re a big coral wholesaler. Those are probably the people that Katherine was dealing with.”

  Violet reached down to pet the tabby cat who was rubbing against her legs. “At least we know now that Horace didn’t scratch Katherine.” She saw the surprised look on Nick’s face. “Her legs were all scratched from the mangrove trees on Melanie’s island, and she blamed it on poor Horace.”

  “Breaking into someone’s cabin is against camp rules,” Melanie said sternly to Joshua Slade. “You won’t be welcome here again.”

  “I’m sorry about that,” Joshua said softly. He looked at his wife and they turned and walked back to their cabin.

  “All those times they acted friendly,” Violet remarked, “they were just trying to see if we knew about any sunken treasure.”

  Benny stifled a yawn. “I can’t believe the mystery is all solved,” he said sleepily.

  “And just in time,” Violet said. She glanced at her watch. “Grandfather will be here in just a few hours to pick us up.”

  “You did a great job, kids,” Nick said.He stepped through the crowd to shake hands with each of them. “Without you, Katherine could have moved on to other sites and other coral beds. It might have taken months, or even years, to catch up with her.”

  “I’m glad we could help,” Henry said. He looked at Benny, who was leaning against him with his eyes half closed. “But now I think it’s time to say good night. My little brother is sleeping standing up.”

  “I’m awake,” Benny protested drowsily. As soon as Henry lifted him up, Benny’s eyes shut and he snuggled against his older brother.

  “Good night,” Melanie said softly. “I’ll see you in the morning before you leave. Let’s have breakfast together.”

  Grandfather arrived bright and early the following morning. “I’m so glad to see you!” he said, hugging Violet, Jessie, Henry, and Soo Lee. They were already packed and waiting by the camp entrance. “We spent days out on the water,” Jessie said. “It was wonderful.”

  “But where’s Benny?” Grandfather asked, looking around.

  “He’s here,” Violet said playfully. “He’s down by the shore. He has something special he wants to show you.” She took Grandfather’s hand. “Come on, I’ll take you there.”

  “Whatever you say,” Grandfather said good-naturedly. He was so happy to see his grandchildren. He missed them, even if they were only away for a few days.

  “Tell us about your trip, Grandfather,” Henry said.

  “It was very relaxing,” Grandfather began. “I did a little sailing and I—” He broke off suddenly as they approached the beach. “Is that Benny?”

  “It sure is!” Jessie said proudly.

  All the children watched as a small figure skimmed over the water on a bright red windsurfer.

  Henry whistled under his breath. “He really got the hang of it,” he said admiringly.“He wanted you to be proud of him, Grandfather.”

  “Well, I am,” Mr. Alden replied, waving to Benny as he zigzagged toward the shore. “I’m proud of all my grandchildren.” He moved forward to greet Benny as he neared the shore. “And what have the rest of you been doing while Benny learned windsurfing? Did anything special happen?”