“But how do you know this?” Naida persisted.

“You heard what I told you in the box,” was the quiet reply.  “I shall explain—­as much as I can explain—­to Nigel when we get home.  He can tell you everything later on to-day at lunch-time, if you like.”

“It has been one of the strangest nights I ever remember,” Naida declared, after a brief pause.  “Oscar Immelan, who was dining with us, arrived half an hour late.  I have never seen him in such a condition before.  He had the air of a broken man.”

“Have you any idea of what had happened?” Nigel asked.

“Only this,” Naida replied.  “We saw Prince Shan last night.  He spent several hours with us.  I may be wrong, but I came to the conclusion then that he had at any rate modified his views about the whole situation since his arrival in England.”

Again there was a brief silence.  The minds of all three of them were busy with the same thought.  Prince Shan’s word had been spoken and Immelan’s hopes dashed to the ground,—­and within a few hours, this murder!  They nursed the thought, but no one put it into words.

A sleepy-eyed porter opened the door of the car outside the Milan Court.  Naida gathered herself together with a little shiver.

“I think that after to-night,” she said quietly, “there need be no secrets between any of us.”

Nigel held her hand in his.  Their eyes met, and both of them were conscious, in that moment, of closer personal relations, of the passing of a certain sense of strain.  She even smiled as she turned away.

“To-morrow,” she concluded, “there must be a great exchange of confidences.  I am lunching at Belgrave Square, if Maggie has not forgotten, and I shall tell you then what I have written to Paul Matinsky.  I showed it to Prince Shan yesterday.  Good night!”

She patted Maggie’s hand affectionately and flitted away.  The revolving doors closed behind her, and the car swung out once more into the Strand, glided down the Mall, past Buckingham Palace, and stopped at last before the great, lifeless house in Belgrave Square.  Nigel opened the front door with a latchkey and turned on the light.

“You won’t mind sparing me a few minutes?” he begged.

“I suppose not,” she answered, shivering.

He led the way to the study.  She threw off her cloak and sank into the depths of one of the big easy-chairs.  She looked very frail and rather pathetic as she leaned her head against the chair back.  Now that the excitement was over, the strain of the emotion she had experienced showed in the violet shadows under her eyes and in the droop of her shoulders.

“I am tired,” she said plaintively.

Nigel came over and sat on the arm of her chair.

“Tell me what happened to-night, Maggie.”

“The little Chinese girl sent for me to go to her box,” she explained.  “She told me where in Prince Shan’s house were hidden the papers which revealed the understanding between Immelan and himself.  She gave me a key of the house and a key of the cabinet.  We could both see the man whom I believed to be Prince Shan seated in his box.  She assured me that he would be there for the next two hours.  I went to the house in Curzon Street.”