“Ssh!” O’Hagan raised his hand. “I will explain later, Raymond. Exhibit no surprise. Merely agree with me—tacitly agree!”

“But where did——”

“Ssh!”—impatiently. “These servants are spies!”

I felt curiously like a screw-stoppered bottle of some highly aerated mineral, which has been partially unscrewed. Questions literally sizzled from me. But I must perforce contain myself; and we were presently rejoined by the Grand Duke. He glanced up and down the street ere entering. Giving a brief order to the man:

“Where are they?” he growled, as he took his seat.

“They have left their car,” replied my friend; “but two of them are in hiding near the corner.”

“Do you know either of these?”

“He is one!” said O’Hagan impressively.

“Whom?” snapped the Grand Duke.

Now, Captain O’Hagan is rarely at a loss for the right word at the right time. He holds it churlish to stammer and stutter, and wholly inconsistent with that grand manner of which, if I be not mistaken, he is the only surviving master. Yet, now, he seemed somewhat taken aback. Later, I understood why. But——