It was a wet Wednesday in the offices of the International Detective Agency. Tuppence let the Daily Leader fall idly from her hand.

"Do you know what I've been thinking, Tommy?"

"It's impossible to say," replied her husband. "You think of so many things, and you think of them all at once."

"I think it's time we went dancing again."

Tommy picked up the Daily Leader hastily.

"Our advertisement looks well," he remarked, his head on one side. "Blunt's Brilliant Detectives. Do you realise, Tuppence, that you and you alone are Blunt's Brilliant Detectives? There's glory for you, as Humpty Dumpty would say."

"I was talking about dancing."

"There's a curious point that I have observed about newspapers. I wonder if you have ever noticed it. Take these three copies of the Daily Leader. Can you tell me how they differ one from the other?"

Tuppence took them with some curiosity.

"It seems fairly easy," she remarked witheringly. "One is to-day's, one is yesterday's, and one is the day before's."

"Positively scintillating, my dear Watson. But that was not my meaning. Observe the headline, 'The Daily Leader.' Compare the three-do you see any difference between them?"

"No, I don't," said Tuppence, "and what's more, I don't believe there is any."

Tommy sighed, and brought the tips of his fingers together in the most approved Sherlock Holmes fashion.

"Exactly. Yet you read the papers as much-in fact, more than I do. But I have observed and you have not. If you will look at today's Daily Leader, you will see that in the middle of the downstroke of the D is a small white dot, and there is another in the L of the same word. But in yesterday's paper the white dot is not in DAILY at all. There are two white dots in the L of LEADER. That of the day before again has two dots in the D of DAILY. In fact, the dot, or dots, are in a different position every day."

"Why?" asked Tuppence.

"That's a journalistic secret."

"Meaning you don't know, and can't guess."

"I will merely say this-the practice is common to all newspapers."

"Aren't you clever?" said Tuppence. "Especially at drawing red herrings across the track. Let's go back to what we were talking about before."

"What were we talking about?"

"The Three Arts Ball."

Tommy groaned.

"No, no, Tuppence. Not the Three Arts Ball. I'm not young enough. I assure you I'm not young enough."

"When I was a nice young girl," said Tuppence, "I was brought up to believe that men-especially husbands-were dissipated beings, fond of drinking and dancing and staying up late at night. It took an exceptionally beautiful and clever wife to keep them at home. Another illusion gone! All the wives I know are hankering to go out and dance, and weeping because their husbands will wear bedroom slippers and go to bed at half past nine. And you do dance so nicely, Tommy dear."

"Gently with the butter, Tuppence."

"As a matter of fact," said Tuppence, "it's not purely for pleasure that I want to go. I'm intrigued by this advertisement."

She picked up the Daily Leader again, and read it out.

"I should go three hearts. 12 tricks. Ace of Spades. Necessary to finesse the King."

"Rather an expensive way of learning Bridge," was Tommy's comment.

"Don't be an ass. That's nothing to do with Bridge. You see, I was lunching with a girl yesterday at the Ace of Spades. It's a queer little underground den in Chelsea, and she told me that it's quite the fashion at these big shows to trundle round there in the course of the evening for bacon and eggs and Welsh Rabbits-Bohemian sort of stuff. It's got screened off booths all round it. Pretty hot place, I should say."

"And your idea is-?"

"Three hearts stands for the Three Arts Ball to-morrow night, 12 tricks is twelve o'clock, and the Ace of Spades is the Ace of Spades."

"And what about its being necessary to finesse the King?"

"Well, that's what I thought we'd find out."

"I shouldn't wonder if you weren't right, Tuppence," said Tommy magnanimously. "But I don't quite see why you want to butt in upon other people's love affairs."

"I shan't butt in. What I'm proposing is an interesting experiment in detective work. We need practice."

"Business is certainly not too brisk," agreed Tommy. "All the same, Tuppence, what you want is to go to the Three Arts Ball and dance! Talk of red herrings."

Tuppence laughed shamelessly.

"Be a sport, Tommy. Try and forget you're thirty-two and have got one grey hair in your left eyebrow."

"I was always weak where women were concerned," murmured her husband. "Have I got to make an ass of myself in fancy dress?"

"Of course, but you can leave that to me. I've got a splendid idea."

Tommy looked at her with some misgiving. He was always profoundly mistrustful of Tuppence's brilliant ideas.

When he returned to the flat on the following evening, Tuppence came flying out of her bedroom to meet him.

"It's come," she announced.

"What's come?"

"The costume. Come and look at it."

Tommy followed her. Spread out on the bed was a complete fireman's kit with shining helmet.

"Good God!" groaned Tommy. "Have I joined the Wembley fire brigade?"

"Guess again," said Tuppence. "You haven't caught the idea yet. Use your little grey cells, mon ami. Scintillate, Watson. Be a bull that has been more than ten minutes in the arena."

"Wait a minute," said Tommy. "I begin to see. There is a dark purpose in this. What are you going to wear, Tuppence?"

"An old suit of your clothes, an American hat and some horn spectacles."

"Crude," said Tommy. "But I catch the idea. McCarty incog. And I am Riordan."

"That's it. I thought we ought to practice American detective methods as well as English ones. Just for once I am going to be the star, and you will be the humble assistant."

"Don't forget," said Tommy warningly, "that it's always an innocent remark by the simple Denny that puts McCarty on the right track."

But Tuppence only laughed. She was in high spirits.

It was a most successful evening. The crowds, the music the fantastic dresses-everything conspired to make the young couple enjoy themselves. Tommy forgot his role of the bored husband dragged out against his will.

At ten minutes to twelve, they drove off in the car to the famous-or infamous-Ace of Spades. As Tuppence had said, it was an underground den, mean and tawdry in appearance, but it was nevertheless crowded with couples in fancy dress. There were closed in booths round the walls, and Tommy and Tuppence secured one of these. They left the doors purposely a little ajar so that they could see what was going on outside.

"I wonder which they are-our people, I mean," said Tuppence. "What about that Columbine over there with the red Mephistopheles?"

"I fancy the wicked Mandarin and the lady who calls herself a Battleship-more of a fast Cruiser, I should say."

"Isn't he witty?" said Tuppence. "All done on a little drop of drink! Who's this coming in dressed as the Queen of Hearts-rather a good get up, that."

The girl in question passed into the booth next to them accompanied by her escort who was "the gentleman dressed in newspaper" from Alice in Wonderland. They were both wearing masks-it seemed to be rather a common custom at the Ace of Spades.

"I'm sure we're in a real den of iniquity," said Tuppence with a pleased face. "Scandals all round us. What a row everyone makes."

A cry, as of protest, rang out from the booth next door and was covered by a man's loud laugh. Everybody was laughing and singing. The shrill voices of the girls rose above the booming of their male escorts.

"What about that shepherdess?" demanded Tommy. "The one with the comic Frenchman. They might be our little lot."

"Anyone might be," confessed Tuppence. "I'm not going to bother. The great thing is that we are enjoying ourselves."

"I could have enjoyed myself better in another costume," grumbled Tommy. "You've no idea of the heat of this one."

"Cheer up," said Tuppence. "You look lovely."

"I'm glad of that," said Tommy. "It's more than you do. You're the funniest little guy I've ever seen."

"Will you keep a civil tongue in your head, Denny, my boy. Hullo, the gentleman in newspaper is leaving his lady alone. Where's he going, do you think?"

"Going to hurry up the drinks, I expect," said Tommy. "I wouldn't mind doing the same thing."

"He's a long time doing it," said Tuppence, when four or five minutes had passed. "Tommy, would you think me an awful ass-" She paused.

Suddenly she jumped up.

"Call me an ass if you like. I'm going in next door."

"Look here, Tuppence-you can't-"

"I've a feeling there's something wrong. "I know there is. Don't try and stop me."

She passed quickly out of their own booth, and Tommy followed her. The doors of the one next door were closed. Tuppence pushed them apart and went in, Tommy on her heels.

The girl dressed as the Queen of Hearts sat in the corner leaning up against the wall in a queer huddled position. Her eyes regarded them steadily through her mask, but she did not move. Her dress was carried out in a bold design of red and white, but on the left side of the pattern seemed to have got mixed. There was more red than should have been…

With a cry Tuppence hurried forward. At the same time, Tommy saw what she had seen, the hilt of a jewelled dagger just below the heart. Tuppence dropped on her knees by the girl's side.

"Quick, Tommy, she's still alive. Get hold of the Manager and make him get a doctor at once."

"Right. Mind you don't touch the handle of that dagger,

"I'll be careful. Go quickly."

Tommy hurried out, pulling the doors to behind him Tuppence passed her arm around the girl. The latter made a faint gesture, and Tuppence realised that she wanted to get rid of the mask. Tuppence unfastened it gently. She saw a fresh flower-like face, and wide starry eyes that were full of horror, suffering, and a kind of dazed bewilderment.