The same conditions prevailed on Barn Door Island. The place where Tom had emerged from the tunnel was found, but a short distance back in the passage dirt and rocks were piled up, preventing a further examination being made.
“Maybe they’re walled up in the tunnel under the lake,” suggested Mr. Damon.
“Not likely,” Tom said.
“They probably cleared out after their bold plan didn’t succeed,” Ned remarked.
“Yes, they’ve gone for a time,” Tom admitted. “But that doesn’t mean it’s forever. They’re still at large and they won’t give up so easily. I’m afraid for the success of my airline express plans. But I’m going to work on them.”
That Tom’s fears were well grounded was borne out a few days later when, as the young inventor sat at his desk, his private telephone rang. Tom’s own instrument had a number not in the book and was known only to a few. Unless this number were given to the central operator Tom’s ’phone bell would not ring.
But ring it did on this occasion, and over the wire came this ominous message:
“Look out for yourself, Tom Swift! We’ll get you yet!”
CHAPTER XIV
THE AIRLINE EXPRESS
Like a flash Tom Swift realized that this warning had come from those daring enemies of his who were still at large—the same men, Kenny and Schlump and the two masked ones, who had kidnapped him. He could realize their rage at his escape, their anger at the foiling of their plot to blow the place up by bombs, or, if their intention was not to cause serious damage, but only confusion, during which they might rob—this, too, had been frustrated.