"M M M begins Have located the machine stop Apparently entirely new type stop Tell Manton to be ready stop M M M ends."

"That's our newest code," the Captain explained, "and this is the first time it has been used. Jules learnt it only just before he left. It is very unlikely that the message has been picked up by anyone else, as the wave-length is quite low, but even if it was, no one could decipher the code from such a short message. They would want one very much longer, and even then it would probably take at least a week or ten days of very hard work by a lot of experts."

And he paused.

"I think it would be well now for one of us to be constantly here," he went on. "Perhaps, too, you would like to overhaul your machine so as to have it absolutely ready to get away at a moment's notice. My fellows will give you any help you want and they are all absolutely to be depended upon not to talk."

d.i.c.k soon had the Mohawk ready; indeed there was not much to do after such a short trip as the flight to Verdun. The rest of the day he spent chatting with Captain Le Couteur, finding him a delightful companion and full of enthusiasm on the subject of wireless, of which his knowledge seemed boundless. d.i.c.k felt he could never tire of admiring the wonderfully ingenious devices which the other had invented and put into operation in his underground fortress.

Several more messages, chiefly brief reports, were received from Jules, always heralded by the seven dots and begun with the three M's which signified the secret code number Five. For a few hours everything seemed to be going well. Then, towards evening came graver news, which on being deciphered, read:

"M M M begins Much fear Yvette suspected stop Tell Manton to be ready instant action stop M M M ends."

It could only mean, they realised, that Yvette had been recognised by a German agent and was being closely watched. The position was dangerous.

d.i.c.k spent the next few hours in an agony of suspense. But he could do nothing. His first instinct was to fly to Berlin. But Le Couteur's iron common-sense showed him clearly enough that to do so would be futile. To keep the Mohawk in Germany, even for a single day, would be risky; to try to hide her there for perhaps a week till they got a chance to rescue Yvette would be suicidal.

A sudden swoop, swift and relentless action, and a quick escape were the essentials of success.

Captain Le Couteur was scarcely less anxious than d.i.c.k himself. He had known Yvette since she was a child; they came from the same town in Alsace. But he possessed a brain of ice and restrained d.i.c.k's impetuosity, though guessing shrewdly at its cause.

"The time is not come yet," he declared. "This is a bit of business which must go to the last tick of the dock. Mademoiselle herself would never forgive us if we spoilt everything by undue precipitation, and, after all, Monsieur Manton, France is of even more importance than Mademoiselle Pasquet, much as I admire her."

"I know," d.i.c.k admitted. "But when I think of her, with her war record, which they know all about, falling into the hands of those brutes, I can hardly sit still."

"They have not got her yet and she is very clever," replied Le Couteur.

"Let us hope that she will give them the slip."

But about ten o'clock the following morning the dreaded blow fell.

They were seated in the underground chamber, d.i.c.k ill at ease and full of gloomy forebodings. The apparatus set to receive messages on three-hundred-and-fifty-metres. Suddenly a buzzing noise was emitted from the loud-speaking telephone on the bench.

Seven dots, seven times repeated, clicked out strong and dear!

Surely seconds had never pa.s.sed so slowly! It seemed an age before Captain Le Couteur, his face white as chalk, took down the message which followed, and then referring to the code, read:

"Yvette arrested this morning by Kranzler."

d.i.c.k turned dizzy and the room spun round him as the dreadful significance of the words struck him. Kranzler, of all men! The murderer of Yvette's father and mother, the man whom she had beaten over and over again at his own game of espionage during the war, the man whose sensational attempt to dispose of Rasputin's stolen jewels had been foiled by Yvette's skill and daring! He was, as they knew, a desperate brute who would stick at nothing to feed his revenge.

d.i.c.k was rushing from the room, determined at all hazards to leave for Berlin at once, when Le Couteur seized his arm in a grip of iron.

"Steady, Manton," he said sharply. "Don't be a fool. You'll spoil everything. Sit down and wait for more news."

The words brought d.i.c.k to his senses.

"I'm sorry, Le Couteur," he said, "but I think I went a bit mad. You are quite right. But Kranzler--of all men! You know the story, of course?"

Le Couteur nodded.

"It could hardly be worse," he admitted, "and there's no use disguising the fact. But we must wait for more from Jules. In the meantime I am going to talk to Regnier. He must have more men on the spot. At all costs Mademoiselle must be rescued."

They were soon in touch with the Chief in Paris, who was horrified at the news.

"I will get some more men over at once," he said. "But we can do nothing until we find out where they have taken her. Jules will realise that. You are certain to get another message from him before long."

It was not until later that day that they learned how the arrest had been effected. Yvette, as soon as the position of the German plane had been located, had managed in the guise of a girl seeking work, to sc.r.a.pe acquaintance with one of the maids employed at the big house where the aeroplane was lodged. The girl had actually taken her up to the house and Yvette had coolly applied to the housekeeper for employment. There was, as it happened, no vacancy, but Yvette had used her eyes to good purpose. In the walk from the lodge to the house and back she had caught sight of the shed in which, obviously, the aeroplane was housed, and had noted its exact position in the extensive grounds. Hurrying back to the hotel she had communicated this information to Jules and both were filled with excitement at the important step forward they had made.

Sitting in the lounge of the "Adlon" next morning Jules had seen Kranzler enter. He had started at once to warn Yvette to "lie low," but was just too late. Yvette at that moment came down the staircase and before Jules could interpose had met Kranzler face to face. She was instantly recognised.

With a grin of delight on his evil face the big German bowed profoundly.

"This is indeed a pleasure, Mademoiselle Pasquet!" he said ironically.

Yvette very coolly tried to carry it off.

"Monsieur has, I think, made a mistake," she said in German.

"It's no use, Mademoiselle," was the harsh reply, "I know you perfectly.

You must come with me--or shall I call the police?"

There was obviously nothing for it but to obey, and Yvette was forced to leave the hotel in the clutches of the one man in all Germany she had the greatest reason to fear.

Jules acted promptly. Slipping out of the hotel he hurriedly wheeled to the front a motor-bicycle he had hired to enable him to travel speedily between Berlin and Spandau. He got round just in time to see Kranzler put Yvette into a taxi, and followed them until they alighted at the door of the house in the Koeniggratzer-stra.s.se which was the head-quarters of the German Secret Service. Yvette was taken inside.

To get the news to d.i.c.k was now Jules' first consideration. Knowing something of the methods of the German Secret Service he was reasonably sure that Yvette would be put through a long examination before she was taken to prison, and he decided to run the risk of being absent for a short time to get his message away. He drove hastily in his car out into the country until he found a tree to which his aerial wire could be attached and got off the brief message which conveyed the news to Verdun. Then he returned to watch, and ascertain where Yvette was to be imprisoned.

The taxi was still outside the door when he got back to the Koeniggratzer-stra.s.se. As an excuse for waiting he feigned engine trouble and tinkered with his machine, keeping all the time a close watch on the door opposite.

He had not long to wait. In about half an hour Yvette was brought out, still in the custody of Kranzler, and driven away. Jules followed, and, at length, had the satisfaction of knowing that Yvette was in the big prison outside Spandau. It was a melancholy satisfaction, it is true, but to know where she was was of supreme importance.

Driving to Gaston's farm he soon informed Verdun where Yvette was located and then turned to discuss the position with Gaston.

To his intense surprise and delight, Gaston was able to give him some comfort.

"Of course, it is a great misfortune," he said, "but it might be worse.

They have taken her to the one prison in Germany where we have been able to keep a thoroughly trustworthy agent. He is a warder who pa.s.ses as Herman Fuchs; his real name is Pierre Latour. We shall soon know all about Mademoiselle."

The front of the prison was in dear view from Gaston's farm. Going outside, he called on Jules to help him to move one of three large barrels, each containing a big flowering shrub, which stood side by side in front of the house facing the prison. One of these was taken away, leaving only two.

"We shall have Pierre over here this evening," Gaston chuckled. "That's the signal that I want him."

Sure enough, soon after dark, Pierre appeared. A few words explained the situation. He was off duty now for the night and free to do as he pleased.

"Leave it to me," he said. "I will be back in an hour."

He returned with a rough plan of the section of the prison in which Yvette was confined. Her cell occupied a corner on the first floor at the head of a flight of steps leading down to the big courtyard. If Yvette could get out of her cell it would be an easy matter to reach the door leading to the yard. But to get over the high wall, quite unclimbable, was a difficult problem. The entrance from the roadway was always guarded by two warders who occupied little separate lodges placed one each side the gateway.

"I can get her out of her cell," said Pierre, "but how to get her out of the yard I don't know. I can get a false key to her during the day, but if I were found in that quarter of the prison at night it would mean instant dismissal. On that point the rules are inflexible and we cannot risk it."