An old man — as yet unidentified — and Mayo's Filipino servant were in the plane, handcuffed. It was supposed that they had attempted a robbery at Mayo's home, and that the millionaire had captured them.
Why he had been taking the malefactors away in his plane, however, was a mystery. That was all. The important links were missing. Nothing was said of Stuart Bruxton, stranded in Virginia. No word appeared to tell how Harry Vincent, wounded, was brought to New York in the cabin of a plane.
For that plane was a mystery ship. It had come from nowhere; and had disappeared as mysteriously as the man who had piloted it.
The Shadow had stepped from the dark to destroy the blackmail ring — and to the dark he had returned!