Jacob caught up with Charlotte and Grandpa. “The beach is getting narrower,” he said.
“The tide’s coming in,” said Grandpa. “It’s time we headed back.”
Charlotte groaned. “Do we have to?”
“I’m afraid so,” said Grandpa. “We don’t want to get caught by high tide.”
Reluctantly they turned back. Charlotte walked beside Jacob. “I’m really sorry about the cutlass.” Her forehead puckered. “Please don’t be mad at me anymore, Jacob.”
Jacob thought of what was hidden in his pocket. He smiled to himself. “I’m not mad,” he said.
Charlotte whooshed out a great sigh of relief. She took off her pirate hat and fanned her face. “I’m so thirsty I could drink seawater.”
“Me too,” said Jacob.
“No need for that.” Grandpa looked ahead. “We’ll stop at the rocks and have a quick drink before we head back to the boat.”
They sat on a large flat rock that was balanced on top of two other rocks. “It’s like a chair,” said Charlotte. “There’s room for all of us.”
Grandpa opened his backpack. He took out three bottles of water. He handed one to Charlotte and one to Jacob.
Jacob opened his bottle and took a long, thirsty gulp. He was about to set it down when the bottle slipped through his fingers. As he grabbed for it, his foot accidentally kicked it under the rock they were sitting on.
“I’ll get it,” said Charlotte. She knelt and pulled out the water bottle. “There’s something else in here too.” She lay on her stomach and reached farther.
Jacob crouched beside her. “What is it?”
Charlotte held it up. “It’s just an old bottle,” she said, disappointed.
Jacob reached for the bottle. He held it up to the light. It was a soft greeny-blue, the color of the sea.
“That’s an old one,” said Grandpa. “See the bubbles in the glass?”
Charlotte and Jacob looked closer. Sure enough, there were tiny bubbles all through the glass.
“I think it’s broken,” said Jacob. “The bottom feels rough.”
Grandpa took the bottle. “This one is a real oldie,” he said. “It’s handblown. That’s why it’s rough on the bottom.” He nodded. “This really is a treasure.”
Jacob wasn’t convinced. “What use is an old empty bottle?”
Charlotte stared at it. “This isn’t any old bottle. This was Captain Shark’s bottle. He put a secret message in it. The message said —”
“Stop!” Jacob ordered. “I’m Captain Shark, and I’m the only one who knows what the message said.”