"What clue have I withheld?"

Paul Harley stood up.

"It is useless to discuss the matter further, Colonel Menendez," he
said, coldly.

The Colonel rose also, and:

"Mr. Harley," he replied, and his high voice was ill-controlled, "if I
give you my word of honour that I dare not tell you more, and if,
having done so, I beg of you to remain at least another night, can you
refuse me?"

Harley stood at the end of the table watching him.

"Colonel Menendez," he said, "this would appear to be a game in which
my handicap rests on the fact that I do not know against whom I am
pitted. Very well. You leave me no alternative but to reply that I will
stay."

"I thank you, Mr. Harley. As I fear I am far from well, dare I hope to
be excused if I retire to my room for an hour's rest?"

Harley and I bowed, and the Colonel, returning our salutations, walked
slowly out, his bearing one of grace and dignity. So that memorable
luncheon terminated, and now we found ourselves alone and faced with a
problem which, from whatever point one viewed it, offered no single
opening whereby one might hope to penetrate to the truth.