"Sheila, Grant is right," said Austin gravely. "You must rest, even if you cannot sleep. You will need all your strength for to-morrow, perhaps for many days yet, before we get to the heart of this mystery. Let the servants go back to bed. Grant and I will wait through the night, in case good news may come to us." There were times when, as the old butler remembered, she had been a very wilful Sheila, but she showed no signs of wilfulness now. The grave tones and words of Austin moved her to obedience. "I will do as you tell me," she said in a hushed and broken voice. "I will go and rest--not to sleep, till I have news of my darling father." Through the weary hours of the night, the two men watched and dozed by turns, waiting in the vain hope of word or sign of Reginald Monkton. None came, and in the early morning Sheila stole down and joined them. Her bearing was more composed, and she had washed away the traces of her tears. "I intend to be very brave," she told them. "I have roused the maids, and I am going to give you breakfast directly, after your long vigil." Impulsively she stretched out a hand to each, the youthful lover and the aged servitor. "You are both dear, good friends, and my father will thank you for your care when he comes back to me." Moved by a common impulse the two men, the young and the old, bent and imprinted a reverent kiss on the slender hands she extended to them. It was a moment of exquisite pathos, the fair, slim girl, resplendent yesterday in the full promise of her youth and beauty; to-day stricken with grief and consumed with the direst forebodings of the fate of a beloved father. CHAPTER FOUR. THE MAN WHO KNEW. Three days had gone by, and the mystery of Reginald Monkton's disappearance remained as insoluble as ever. Well, it might be so, since there did not seem a single clue, with the exception of the name muttered by the dying man, which at first had sounded like Molyneux, and afterwards like Mulliner. Neither Sheila nor Grant, who had listened to those faint sounds issuing from the dying lips, could be certain which of the two was correct. Wingate had seen Smeaton twice, and that astute person assured him that the keenest brains at Scotland Yard were working on the case. But he was very reticent, and from his manner the young man was forced to draw the conclusion that the prospects of success were very slight. If it had been simply a case of disappearance, uncomplicated by other circumstances, many theories could have been formed. There were plenty of instances of men whose reason had become temporarily unhinged, and who had lost consciousness of their own identity. Again, men have disappeared voluntarily because they have been threatened with exposure of some shameful secret of the past, and will willingly pay the penalty of separation from their own kith and kin to avoid it.