“So, Uncle Charlie is going to be mysterious again,” Biff said to himself. Biff sprawled out on the bed and waited for Uncle Charlie to start talking.

“It all goes back to our days in Burma and China, Biff. You know Explorations Unlimited still has its headquarters in Burma. Sumatra’s not too far from Burma. Lots of Dutch people in Sumatra. It was once a Dutch colony. And Explorations had done quite a bit of work for some of the Dutch businessmen there.

“Just after we had to get out of Burma—you remember, of course—Explorations received an inquiry as to whether its operations extended to the Netherlands Antilles. Jack Hudson—you recall him, don’t you, Biff?—cabled me.”

Biff nodded his head. Jack Hudson also worked for Explorations Unlimited. It had been Jack who had flown into China and rescued Biff and his uncle when Biff had taken part in the Mystery of the Chinese Ring.

“So Jack cabled me,” Uncle Charlie went on. “An inquiry had come from a friend of Derek’s father, Brom Zook. Brom wanted someone to work for and with him. I got the job. I’d picked up a seaplane with my earnings in China and had been kicking around the Caribbean, charter flights and so on.”

“What did he want you to do?” Biff asked.

“Pilot him back and forth from here to Martinique. Run a speedboat he has in Martinique.”

“I know from what Dietz told me that Derek’s father is looking for something on the bottom of the ocean? What is it? Sunken treasure?” Biff asked.

“In a way, yes. And he’s found it, too. It’s a pearl fishery—”

“Pearl fishery!” Biff’s voice showed his excitement.