"Was his disappearance reported?"
"Of course it was.
His wife came to us in a great state.
We did what we could, but I knew all along it would be no good."
"Why not?"
"Never is - when a man disappears that way." Japp winked.
"What way?"
"Paris."
"So Halliday disappeared in Paris?"
"Yes.
Went over there on scientific work - so he said.
Of course, he'd have to say something like that.
But you know what it means when a man disappears over there.
Either it's Apache work, and that's the end of it - or else its voluntary disappearance - and that's a great deal the commoner of the two, I can tell you.
Gay Paree and all that, you know.
Sick of home life. Halliday and his wife had had a tiff before he started, which all helps to make it a pretty clear case."
"I wonder," said Poirot thoughtfully.
The American was looking at him curiously.
"Say, mister," he drawled, "what's this Big Four idea?"
"The Big Four," said Poirot, "is an international organisation which has at its head a Chinaman.
He is known as Number One.
Number Two is an American. Number Three is a Frenchwoman.
Number Four, the 'Destroyer,' is an Englishman."
"A Frenchwoman, eh?" The American whistled. "And Halliday disappeared in France.
Maybe there's something in this.
What's her name?"
"I don't know.
I know nothing about her."
"But it's a mighty big proposition, eh?" suggested the other.
Poirot nodded, as he arranged the glasses in a neat row on the tray.
His love of order was as great as ever.
"What was the idea in sinking those boats?
Are the Big Four a German stunt?"
"The Big Four are for themselves - and for themselves only, M. le Capitaine.
Their aim is world domination."
The American burst out laughing, but broke off at the sight of Poirot's serious face.
"You laugh, monsieur." said Poirot, shaking a finger at him. "You reflect not - you use not the little gray cells of the brain.
Who are these men who send a portion of your navy to destruction simply as a trial of their power?
For that was all it was. Monsieur, a test of this new force of magnetical attraction which they hold."
"Go on with you, moosior," said Japp good-humouredly. "I've read of super criminals many a time, but I've never come across them.
Well, you've heard Captain Kent's story.
Anything further I can do for you?"
"Yes, my good friend.
You can give me the address of Mrs. Halliday - and also a few words of introduction to her if you will be so kind."
Thus it was that the following day saw us bound for Chetwynd Lodge, near the village of Chobham in Surrey.
Mrs. Halliday received us at once, a tall, fair woman, nervous and eager in manner.
With her was her little girl, a beautiful child of five.
Poirot explained the purpose of our visit.
"Oh!
Monsieur Poirot, I am so glad, so thankful.