Now, for the first time, Ned noted that a fierce gale was blowing from the west, and his thoughts went back to the plateau where the aeroplane lay exposed to the storm. He ran back to the cavern, barely escaping being blown off his feet on the way, and called to the boys.

“There’s a stiff wind blowing,” he said, “and I’m afraid for the aeroplane. We must get back to the camp immediately.”

“The wind was on when I came in,” Jimmie said, “an’ it near blew me into the lake, even if I did hold on to the trees. We can never make the hill in the storm.”

“We’ve got to,” Ned insisted.

“Besides,” Jimmie continued, “we want to find out about the dead man Frank has been telling me about. We can’t take him with us, an’ he will not be here when we come back. Whatever we learn about him, an’ the cause of his death, must be learned now.”

“Sometimes, Jimmie,” Frank burst out, “you exhibit signs of almost human intelligence!”

“The boy is right,” Ned observed. “I’m so rattled that I hardly know what I’m about. We ought to be in pursuit of that rascal who is rowing on the lake, we ought to be on the plateau, looking after the aeroplane, and we ought to be here, finding out if a murder has been committed.”

“It is a murder, all right,” Frank said, “for the floor in the tunnel is sticky with blood.”

“I’m goin’ in there!” Jimmie exclaimed.

“Go if you want to,” Frank grunted.