They walked out, and Caldew locked the door behind him and placed the key in his pocket. When they reached the entrance hall Colwyn paused outside the door of the recess where the housekeeper lurked, like an octopus in a pool. At Colwyn's knock a white face, topped by a white cap, came into view through the narrow slit in the curtained glass half of the door, and swam towards them in the interior gloom after the manner of the head of a materialized ghost in a spirit medium's parlour. The door opened, and the apparition appeared in the flesh, looking at them with stony eyes. Caldew undertook the conversation: "Did Captain Nepcote sleep here last night?" he curtly asked. "I don't know." "Well, has he been here this morning?" "I don't know." The tone of the second reply was even more expressionless than the first, if that were possible. "It's your business to know," said Caldew angrily. "It is not my business to discuss Captain Nepcote's private affairs with strangers." The woman turned back into her room without another word, closing the door behind her. "D--n her!" muttered Caldew, in intense exasperation. "These ancient females learn the wisdom of controlling their natural garrulity when placed in charge of bachelors' flats," said Colwyn with a laugh. "We will get nothing out of her if we stay here all day, so we had better go." "I am going straight back to Scotland Yard," Caldew announced with sudden decision when they reached the pavement. "I must tell Merrington all about this morning's work, and the sooner the better. We must have the flat watched. Perhaps Nepcote may return." "He will not return," said Colwyn. "He knows that we are after him, and that the flat will be watched. But it is a good idea not to let him have too long a start. Come, let us see if we can find a taxi, and I will drop you at Scotland Yard." They walked along to Sherryman Square, and esteemed themselves fortunate in picking up a cruising taxi-cab with a driver sufficiently complaisant to drive them in the direction they wished to go. CHAPTER XXII It was to Merrington's credit as an official that he suppressed his feelings as a man on hearing Caldew's story, and did everything possible to retrieve the situation once he was convinced that Nepcote had fled. Any lingering doubts he may have had were scattered on learning, after confidential inquiry at Whitehall, that Captain Nepcote had not put in an appearance at the War Office that day, and had neither requested nor been granted leave of absence from his duties.