“Why?”

“The doctor, Mr. Mannering, wished him to do so.  He desired to have a companion.”

“Have you anything further that you would care to tell us?”

“Only this, that I think Mr. Hardcastle, with whom I had a long conversation on his arrival, gave it as his opinion that it was not in the Grey Room we must look for an explanation.  I believe he regarded his visit to the room itself as a comparatively unimportant part of the case.  He was really more interested in the life of my son-in-law and his relations with other people.  I think he regarded May’s death as a matter which had been determined outside the Grey Room.  But, if I may presume to advise you, this view of his is surely proved mistaken in the light of his own destruction and what has happened since.  It is certain now that the cause of danger lies actually in the room itself, and equally certain that what killed my son-in-law also killed Mr. Hardcastle and, last night, killed the Reverend Septimus May.”

“On the fact of it, yes,” admitted Frith.  “I think, after we have considered the situation now developed and visited the Grey Room, we shall agree that there, at any rate, we may begin the work that has brought us.  You understand we rule out the possibility of any supernatural event, as Hardcastle, of course, did.  While he very properly centred on the history of Captain May, and, from his point of view, did not expect to find the accident of the captain’s death in this particular place would prove important, we shall now assume otherwise, and give the room, or somebody with access to it, the credit for this destruction of human life.  We shall fasten on the room therefore.  Our inquiry is fairly simple at the outset, simpler than poor Hardcastle’s.  It will lie along one of two channels, and it depends entirely upon which channel we have to proceed whether the matter is going to take much time, and possibly fail of explanation at the end, or but a short time, and be swiftly cleared up.  I hope the latter.”

“I shall be glad if you can explain that remark,” answered Sir Walter; but Mr. Frith was not prepared immediately to do so.

“Fully when the time comes, Sir Walter; but for the moment, no—­ not even to you.  You will understand that our work must be entirely secret, and the lines on which we proceed known only to ourselves.”

“That is reasonable, for you cannot tell yet whether I, who speak to you, may not be responsible for everything.  At least, command me.  I only hope to Heaven you are not going to discover a great crime.”

“I share your hope.  That is why I speak of two channels for inquiry,” answered the detective.  “Needless to say, we four men shall discuss the new light thrown upon the situation very fully.  At present the majority of us are inclined to believe there is no crime, and the death of Mr. May does not, to my mind, increase the likelihood of such a thing.  Indeed, it supports me, I should judge, in my present opinion.  What that is will appear without much delay.  We’ll get to our quarters now, and ask to see the Grey Room later on.”