The Weight of the Crown by Fred M. White

Here was a danger that Jessie had not expected. She was not surprised to see Prince Boris Mazaroff there; indeed, she would not have been surprised at anything after the events of the last few hours. There was no startling coincidence in the presence of the Russian here, seeing that he know everybody worth knowing in London, and all society would be here presently.

Would he come forward and speak? Jessie wondered. She would have avoided the man, but then it seemed to be quite understood that she must stay by the fountain till the signal was given. All this had been evidently carefully thought out before Vera Galloway found it an imperative necessity to be elsewhere on this fateful night.