“A little diplomatic errand,” repeated the Foreign Secretary.  “In itself the thing is not much:  that is, on the face of it.  And yet, in its relation with other interests, it becomes a mission of vast importance, incalculable importance.  When I have explained, you will see why I apply to you.  Indeed, I came to my cousin Mountstuart’s house expressly because I was told you would be at his wife’s ball.  My regret is, that the news which brought me in search of you didn’t reach me earlier, for if it had I should have come with my wife, and have got at you in time to send you off—­if you agreed to go—­to-night.  As it is, the matter will have to rest till to-morrow morning.  It’s too late for you to catch the midnight boat across the Channel.”

“Across the Channel?” echoed Ivor.  “You want me to go to France?”

“Yes.”

“One could always get across somehow,” said Ivor, thoughtfully, “if there were a great hurry.”

“There is—­the greatest.  But in this case, the more haste, the less speed.  That is, if you were to rush off, order a special train, and charter a tug or motor boat at Dover, as I suppose you mean, my object would probably be defeated.  I came to you because those who are watching this business wouldn’t be likely to guess I had given you a hand in it.  All that you do, however, must be done quietly, with no fuss, no sign of anything unusual going on.  It was natural I should come to a ball given by my wife’s sister, whose husband is my cousin.  No one knows of this interview of ours:  I believe I may make my mind easy on that score, at least.  And it is equally natural that you should start on business or pleasure of your own, for Paris to-morrow morning; also that you should meet Mademoiselle de Renzie there.”

“Mademoiselle de Renzie!” exclaimed Ivor, off his guard for an instant, and showing plainly that he was taken aback.

“Isn’t she a friend of yours?” asked the Foreign Secretary rather sharply.  Though I couldn’t see him, I knew exactly how he would be looking at Ivor, his keen grey eyes narrowed, his clean-shaven lips drawn in, the long, well-shaped hand, of which he is said to be vain, toying with the pale Malmaison pink he always wears in his buttonhole.

“Yes, she is a friend of mine,” Ivor answered.  “But—­”

“A ‘but’ already!  Perhaps I’d better tell you that the mission has to do with Mademoiselle de Renzie, and, directly, with no one else.  She has acted as my agent in Paris.”

“Indeed!  I didn’t dream that she dabbled in politics.”

“And you should not dream it from any word of mine, Mr. Dundas, if it weren’t necessary to be entirely open with you, if you are to help me in this matter.  But before we go any further, I must know whether Mademoiselle de Renzie’s connection with this business will for any reason keep you out of it.”

“Not if—­you need my help,” said Ivor, with an effort.  “And I beg you won’t suppose that my hesitation has anything to do with Miss de Renzie herself.  I have for her the greatest respect and admiration.”