He had heard that The Shadow was aided by mysterious agents; and fanciful stories had been built about them.

I was rapidly losing faith in that mysterious agent who was supposed to have used it before me.

Why, what the devil do you make of all that nonsense about a mysterious agent which would signal our whereabouts?

You tell me an horrid tale of Wieland being led to the destruction of his wife and children, by some mysterious agent.

An attack by mysterious agents causes Nathan to be moved to the protective custody of the Starjammers.

A mysterious Russian agent is the mastermind.

Cadet Tifflor has found out that the mysterious agents are our own robots-or at least some of them are.

Suspicion over the disappearance soon turns on the mysterious secret agent and he also disappears.

Was I about to be struck down by the same mysterious agent?

Length: 12 minutes Max's mission to retrieve a dangerous device in a violent storm is foiled by a mysterious agent.