"Good. I will call upon her about ten o'clock. What time are you supposed to return?"

"About nine-thirty or ten, but I could go back earlier."

"You must not do that on any account. It might arouse suspicion if you did not stay out till the usual time. Be back by nine-thirty. I will arrive at ten. Mr. Hersheimmer will wait below in a taxi perhaps."

"He's got a new Rolls-Royce car," said Tuppence with vicarious pride.

"Even better. If I succeed in obtaining the address from her, we can go there at once, taking Mrs. Vandemeyer with us if necessary. You understand?"

"Yes." Tuppence rose to her feet with a skip of delight. "Oh, I feel so much better!"

"Don't build on it too much, Miss Tuppence. Go easy."

Julius turned to the lawyer.

"Say, then. I'll call for you in the car round about nine-thirty. Is that right?"

"Perhaps that will be the best plan. It would be unnecessary to have two cars waiting about. Now, Miss Tuppence, my advice to you is to go and have a good dinner, a REALLY good one, mind. And don't think ahead more than you can help."

He shook hands with them both, and a moment later they were outside.

"Isn't he a duck?" inquired Tuppence ecstatically, as she skipped down the steps. "Oh, Julius, isn't he just a duck?"

"Well, I allow he seems to be the goods all right. And I was wrong about its being useless to go to him. Say, shall we go right away back to the Ritz?"

"I must walk a bit, I think. I feel so excited. Drop me in the park, will you? Unless you'd like to come too?"

"I want to get some petrol," he explained. "And send off a cable or two."

"All right. I'll meet you at the Ritz at seven. We'll have to dine upstairs. I can't show myself in these glad rags."

"Sure. I'll get Felix help me choose the menu. He's some head waiter, that. So long."

Tuppence walked briskly along towards the Serpentine, first glancing at her watch. It was nearly six o'clock. She remembered that she had had no tea, but felt too excited to be conscious of hunger. She walked as far as Kensington Gardens and then slowly retraced her steps, feeling infinitely better for the fresh air and exercise. It was not so easy to follow Sir James's advice, and put the possible events of the evening out of her head. As she drew nearer and nearer to Hyde Park corner, the temptation to return to South Audley Mansions was almost irresistible.

At any rate, she decided, it would do no harm just to go and LOOK at the building. Perhaps, then, she could resign herself to waiting patiently for ten o'clock.

South Audley Mansions looked exactly the same as usual. What Tuppence had expected she hardly knew, but the sight of its red brick stolidity slightly assuaged the growing and entirely unreasonable uneasiness that possessed her. She was just turning away when she heard a piercing whistle, and the faithful Albert came running from the building to join her.

Tuppence frowned. It was no part of the programme to have attention called to her presence in the neighbourhood, but Albert was purple with suppressed excitement.

"I say, miss, she's a-going!"

"Who's going?" demanded Tuppence sharply.

"The crook. Ready Rita. Mrs. Vandemeyer. She's a-packing up, and she's just sent down word for me to get her a taxi."

"What?" Tuppence clutched his arm.

"It's the truth, miss. I thought maybe as you didn't know about it."

"Albert," cried Tuppence, "you're a brick. If it hadn't been for you we'd have lost her."

Albert flushed with pleasure at this tribute.

"There's no time to lose," said Tuppence, crossing the road. "I've got to stop her. At all costs I must keep her here until--" She broke off. "Albert, there's a telephone here, isn't there?"

The boy shook his head.

"The flats mostly have their own, miss. But there's a box just round the corner."

"Go to it then, at once, and ring up the Ritz Hotel. Ask for Mr. Hersheimmer, and when you get him tell him to get Sir James and come on at once, as Mrs. Vandemeyer is trying to hook it. If you can't get him, ring up Sir James Peel Edgerton, you'll find his number in the book, and tell him what's happening. You won't forget the names, will you?"

Albert repeated them glibly. "You trust to me, miss, it'll be all right. But what about you? Aren't you afraid to trust yourself with her?"

"No, no, that's all right. BUT GO AND TELEPHONE. Be quick."

Drawing a long breath, Tuppence entered the Mansions and ran up to the door of No. 20. How she was to detain Mrs. Vandemeyer until the two men arrived, she did not know, but somehow or other it had to be done, and she must accomplish the task single-handed. What had occasioned this precipitate departure? Did Mrs. Vandemeyer suspect her?

Speculations were idle. Tuppence pressed the bell firmly. She might learn something from the cook.

Nothing happened and, after waiting some minutes, Tuppence pressed the bell again, keeping her finger on the button for some little while. At last she heard footsteps inside, and a moment later Mrs. Vandemeyer herself opened the door. She lifted her eyebrows at the sight of the girl.

"You?"

"I had a touch of toothache, ma'am," said Tuppence glibly. "So thought it better to come home and have a quiet evening."

Mrs. Vandemeyer said nothing, but she drew back and let Tuppence pass into the hall.

"How unfortunate for you," she said coldly. "You had better go to bed."

"Oh, I shall be all right in the kitchen, ma'am. Cook will--"

"Cook is out," said Mrs. Vandemeyer, in a rather disagreeable tone. "I sent her out. So you see you had better go to bed."

Suddenly Tuppence felt afraid. There was a ring in Mrs. Vandemeyer's voice that she did not like at all. Also, the other woman was slowly edging her up the passage. Tuppence turned at bay.

"I don't want--"

Then, in a flash, a rim of cold steel touched her temple, and Mrs. Vandemeyer's voice rose cold and menacing:

"You damned little fool! Do you think I don't know? No, don't answer. If you struggle or cry out, I'll shoot you like a dog."

The rim of steel pressed a little harder against the girl's temple.

"Now then, march," went on Mrs. Vandemeyer. "This way-into my room. In a minute, when I've done with you, you'll go to bed as I told you to. And you'll sleep-oh yes, my little spy, you'll sleep all right!"

There was a sort of hideous geniality in the last words which Tuppence did not at all like. For the moment there was nothing to be done, and she walked obediently into Mrs. Vandemeyer's bedroom. The pistol never left her forehead. The room was in a state of wild disorder, clothes were flung about right and left, a suit-case and a hat box, half-packed, stood in the middle of the floor.

Tuppence pulled herself together with an effort. Her voice shook a little, but she spoke out bravely.

"Come now," she said. "This is nonsense. You can't shoot me. Why, every one in the building would hear the report."

"I'd risk that," said Mrs. Vandemeyer cheerfully. "But, as long as you don't sing out for help, you're all right-and I don't think you will. You're a clever girl. You deceived ME all right. I hadn't a suspicion of you! So I've no doubt that you understand perfectly well that this is where I'm on top and you're underneath. Now then-sit on the bed. Put your hands above your head, and if you value your life don't move them."

Tuppence obeyed passively. Her good sense told her that there was nothing else to do but accept the situation. If she shrieked for help there was very little chance of anyone hearing her, whereas there was probably quite a good chance of Mrs. Vandemeyer's shooting her. In the meantime, every minute of delay gained was valuable.

Mrs. Vandemeyer laid down the revolver on the edge of the washstand within reach of her hand, and, still eyeing Tuppence like a lynx in case the girl should attempt to move, she took a little stoppered bottle from its place on the marble and poured some of its contents into a glass which she filled up with water.