Frank was preparing to spring to his feet.
"Listen, Captain Royal," he said placatingly. "Let me go this time and I promise I won't bother you again."
But the captain shook his head.
"You're a spy!" he screeched. "You're a spy! You were sent here to look through all my papers. I'm an old sailor, I am, and in the navy we have only one cure for spies."
"And what's that?"
"We shoot 'em." Captain Royal brandished the shotgun viciously. "We shoot 'em when we can't make 'em walk the plank."
"You haven't the nerve to shoot me. You wouldn't dare. You know you'd be hanged."
Frank glanced toward the mouth of the cave. Joe was almost safe by now.
"I'm not afraid!" bragged Captain Royal. "They'd never catch me to hang me. Death for the spies. I'll shoot both of you—"
Only then did he become aware that Joe had disappeared. With a growl of alarm, he swung about, just in time to see Joe vanishing beyond the cave-mouth.