“Not a word. What can I say? I have asked Miss West to refrain from uttering a syllable—also the Finlays have promised entire secrecy.”

“There is a motive in her disappearance, Hartwig,” I said. “What is it?”

“Ah! That’s just it, Mr Trewinnard,” he replied. “Her Highness had no motive whatever to disappear. Mr Drury was always welcome at Brunswick Square, for Miss West entirely approved of him. Besides, his presence had prevented other flirtations. Therefore there was no reason that there should have been any clandestine meeting in Eastbourne.”

“Then the only other suggestion is that of treachery.”

“Exactly. And that is the correct one—depend upon it.”

“If she has fallen into Markoff’s hands then she may be already dead!” I gasped, staring at him. “If so, the secret will remain a secret for ever!”

For a moment the great detective remained silent. Then slowly he said:

“To tell the truth, that is exactly what I fear. Yes, I will try and suppress the horrible apprehension. It is too terrible.”

“Danilovitch is unscrupulous,” I said, “and he hates us.”

“No doubt he does. He fears us, yet—” and he paused. “Yet a most curious point is the fact that Her Highness deliberately remained behind and sent Dmitri on, in order to be allowed opportunity to escape his vigilance.”