“A fortunate chance intervened,” Immelan replied.

“Fortunate?”

Immelan watched Nigel’s retreating figure with a menacing frown.

“I find it so,” he replied.  “Our wonderful prima donna is in great voice to-night—­and I like to be prepared for all possible combinations.”

CHAPTER XI

Maggie came suddenly into the library at Belgrave Square, where Jesson, Chalmers and Nigel were talking together.  She carried in her hand a note, which she handed to the latter.

“Naida is a dear, after all,” she declared.  “There is one person at least who does not wish to have me pass away in a German nursing home or fall a victim to Frau Essendorf’s cooking.”

Nigel read the note aloud.  It consisted of only a sentence or two and was dated from the Milan Court that morning: 

     Maggie dear, this is just a line of advice from your friend.  You
     must not go back to Germany.

     Naida.

“I fear,” Maggie sighed, “that my little expedition is scotched, even if I had been able to persuade you others to let me go.  Every one seems to have made up their mind that I shall not go to Germany.  It will be such a disappointment to those flaxen-haired atrocities, Gertrud and Bertha.  Their so-much-loved Miss Brown can never return to them again.”

“In any case, the game was scarcely worth the candle,” Nigel observed.  “We have already all the evidence we require that some scheme inimical to this country is being proposed and fostered by Immelan.  Our next move must be to find out the nature of this scheme—­whether it be naval, military, or political.  I don’t think Essendorf would be at all likely to give away any more interesting information in the domestic circle.”

“What are we all going to do, then?” Maggie asked.

“We are met here to discuss it,” Nigel replied.  “Jesson is off to Russia this afternoon.  I asked him to come round and have a few last words with us, in case there was anything to suggest for us stay-at-homes.”

“We shall have to rely very largely upon luck,” Jesson declared.  “There are three places, in any of which we might discover what we want to know.  One is Kroten, another is Paris, provided that Prince Shan really goes there, and the third London.”

“London?” Maggie repeated.

“There are two people in London,” Jesson declared, “who know everything we are seeking to discover.  One is Immelan and the other Naida Karetsky.”

“It seems to me,” Maggie said, “that if that is so, the place for us is where those two people are.  What is the importance of Kroten, Mr. Jesson?”

“Kroten,” Jesson replied, “is the second of what I have seen referred to in a private diplomatic report, written in an enemy country, as the three mystery cities of the world.  The first one is in Germany, and I have already explored it.  I have information, but information which without its sequel is valueless.  Kroten is the second.  Ten years ago it was a town of eighteen thousand inhabitants.  To-day there are at least two hundred thousand people there, and it is growing all the time.”