As Stone surmised, Iris was kidnapped again. When she leaned down to gather in her arms the little, yelping dog, a figure sprang from the shrubbery, and pressing a cloth into and over her mouth a man lifted her from the ground and carried her swiftly away.

Iris was a slender girl and the man had no difficulty in carrying her to a small motor car, which was waiting out in the main road. The dusk rendered them nearly invisible, and the detention of Stone by Lucille precluded what might have been a capture of the invader.

Placed in the car, Iris recognized at once that it was the same one in which she had been carried off before, and she well knew it was for the same purpose—to get possession of the pin.

But now that Stone had told her it was valuable, she had no mind to let it go easily. She sat quietly, as the car flew along, thinking hard what she would better do. She knew Stone would follow and rescue her if he had heard any signs of her departure. But the car made little noise, and the whole affair had been so quickly accomplished that Iris feared Stone knew nothing of it all. She assumed that he would naturally follow her out-of-doors, to learn what had happened to her pet dog, but he might not hasten on that errand, and a delay of a minute would make his advent of small use to her.

They had gone a mile or so, when the car turned into a little used path through the woods. Another man was driving the car, and her captor sat in the back with Iris. He still held her and kept the cloth, which smelled faintly of chloroform, over her mouth.

At last, when well into the woods, the car stopped, and the man got out, and ordered Iris to get out, too.

Her mind was made up now; she meant secretly to draw the pin from her belt, and drop it on the ground. It was running a risk of losing it, but it was a worse risk to have this man take it from her, and, too, after Fibsy's successful search of the coal bin, she felt pretty sure the boy could find the pin in the woods. She was carefully noting the trees and stones about, when the low voice of her tormentor said, "You will hand that pin over at once, if you please."

"I'll do no such thing," Iris retorted with spirit. "I am not afraid of you."

"Nor have you reason to be, if you give up the pin quietly; otherwise, you will find yourself in a sorry predicament."

"I haven't the pin with me," declared Iris, feeling the falsehood justifiable in the circumstances.

"I regret to contradict a lady, but I don't believe you."

The man was masked, but Iris recognized his voice and form and she well knew it was the man who had intruded upon her in her aunt's room that night, and she was sure it was the man who had instigated the kidnapping and search by Flossie. Moreover, she realized it was the man she had seen in Chicago.

She felt an anxiety to detain him and somehow to get him in the grip of the law, but she could think of no way to do that.

She dared not take the pin from her belt, for his eyes were upon her, and the dusk, though deepening, left sufficient light for him to observe her movements.

"Now, look here," he said, speaking more roughly, "there's no Flossie here. You don't want me to take all the pins you have in your clothing, do you?"

This suggestion, and the threatening tone of the man, frightened Iris more than all that had gone before. She was not afraid of physical violence, something in the man's manner precluded that, but she sensed his desperate determination to secure the pin, and she knew he would search her clothing for it, if she refused to hand it over.

Also, she knew there was small use in trying to fool him. Since Stone had verified the fact that there was something about that special pin that made it of value, since this man had tried devious ways to get it, and since she was absolutely at his mercy, the outlook was pretty black.

A vague hope that Fleming Stone would come to her rescue was not well founded, for how could he know that the car that carried her off had turned into that little woodland road?

She thought of appealing to the manliness or better nature of her enemy, but she knew that he would only reply that if she would give him the pin he would not trouble her further. An idea of asking help from the man who was in the driver's seat of the car brought only the same conclusion.

"Come, now," said Pollock, for it was by that name she thought of him. "I can't waste any more time. If you don't give me that pin in two seconds, I'll take it."

"Don't you dare!" exclaimed Iris, trying the effect of sheer bravado.

"Two seconds I'll give you, and they've passed. You needn't scream, for we're far from any habitation."

He came nearer to her, and touched the frill that was about the neck of her gown.

Iris was at her wits' end. She knew she would give up the pin rather than have him search her clothing for it, and yet, she meant to put off her surrender as long as possible.

His own words gave her a hint, and though knowing it could do no good, she screamed loud and long.

The sound infuriated the man, and he sprang at her, grasping her round the waist.

"Stop that!" he cried, "Stop or I'll kill you!"

His fingers were at her throat, and his frenzy was such that Iris feared he would carry out his threat on a sudden impulse.

But the strangle-hold he had on her brought his body near hers, and by chance Iris' hand was flung against his side coat pocket, where she felt what was indubitably an automatic pistol.

Pretending to faint, she let her head sink backward, and he involuntarily put his hand back of her neck to support her.

With a quick motion she snatched the pistol from his pocket without his knowledge.

Exultant, and feeling herself safe, Iris commanded him to release her.

He only laughed, and she whispered faintly, "Let me go, and I'll——"

Her voice died away as if from weakness, and he partially released his hold on her, which freed entirely her right arm.

With a wrench, she stepped back, and aiming the automatic at him, she said, quietly, "Step toward me, and I'll fire!"

With a profane exclamation, Pollock clapped his hand to his side pocket and fell back a pace or two.

"You little vixen!" he cried. "Give me that! You'll harm yourself!"

"Oh, no, I won't. But I'll harm you. Unless you give your driver orders to take me straight back home, I shall make this little weapon give good account of itself."

From where Iris now stood, she covered the two men, and her manner showed no signs of fear, as she calmly informed them that a move on the part of either would be followed by a shot.

"And," she said, "while I'm not an expert, I can manage to hit at this short range."

"Come, come, now, let's arbitrate," said Pollock, who, evidently, knew when he was cornered. "Give me the pin and I'll go halves with you."

"Halves of what?"

"Of the treasure. Oh, don't pretend you don't know all about it! Didn't that old smarty-cat you've got on the job tell you what the pin means?"

"If he did, you don't know," said Iris, talking blindly, for she could make no guess why the pin was a factor in the case at all.

"Don't I? I'm the only one who does know! Your Stone detective can never get a cent's worth of good out of that pin without my help. I'm the only one on earth who knows its secret, or who can turn it to use. So, now, miss, will you make terms? Wait! You needn't take my word for this. Will you agree that if you return safe home with your precious pin, and when your precious detective fails to utilize the pin's secret, you'll let me disclose it to you, and you'll give me half the value of the jewels?"

"I most certainly will not!"

"Then, listen. I swear to you that you will never find those hidden jewels. Only I can tell you what the pin means, and how it leads to your aunt's fortune. Refuse my offer, and neither you nor anyone else will ever see one tiniest gem of your aunt's hoard."

There was something in the man's voice that carried conviction. Iris was a good reader of human nature, and a surety of his truthfulness came over her.

But she was far from willing to accede to his terms.

"I do not entirely disbelieve you," she said, "but I most certainly will not give you the pin——"

"You said you didn't have it!"

"You interrupted me! I was about to say I will not give it to you, even after my return home."

"Then we'll take it now! Come on, Bob."

Evading the pointed pistol by a quick jump, Pollock dashed it from Iris' hand, having really caught her off her guard as she grew interested in their conversation. The driver, Bob, sprang toward them both, and they seized Iris between them.

A terrific scream from the girl rang through the silent woods and as the pistol struck the ground it went off with a fairly loud report.

Iris felt her senses going as the two men clutched her roughly, but managed, in spite of a restraining hand, to give another loud scream.

And it was these sounds that guided Fibsy's flying feet toward the scene of conflict.

He had come with Stone in the car that the detective had used to follow Iris from Pellbrook, but as no one knew which way to look for the kidnapper's car, they had separated, and Stone with Campbell went hunting the highroads, while Fibsy, scenting the truth, had dived into the wood.

He had heard Iris' last scream, also the noise of the automatic, and he blew a loud blast on a shrill whistle, as he hurried to the girl.

Nearing the three, Fibsy's quick eyes saw the pistol on the ground, and he snatched it up, and aimed it straight at the masked man.

"Hands up!" he cried, and Pollock turned to see a small but dauntless-looking boy threatening him.

Again endangered by his own firearm, Pollock stood at bay, raging but impotent in the face of the steady aim of the boy.

In another moment Stone came, with Campbell, in the Pell car and Iris breathed freely once more, as she felt stealthily for the pin in her belt ribbon. It was safe, and she sank down on the ground, satisfied to let the newcomers take charge of the whole matter.

This they did with neatness and dispatch.

Bidding Fibsy keep the two men covered with the small but efficacious weapon, Stone and Campbell tied the hands of Pollock and his man Bob, using the dustrobe from Pollock's car, cut into strips for the purpose.

Then they bundled them unceremoniously into their own car and Stone himself took the wheel.

Campbell drove Iris home, but Fibsy traveled with his chief.

The boy was thrilling with satisfaction at the way things were turning out, and not at all vain-glorious over his own part in the affair.

Stone turned the two men over to the police on a charge of kidnapping and then, elated, returned to Pellbrook.

"How can I be grateful enough to you," Iris cried at sight of the detective, "for coming to my aid! And Fibsy, too! Oh, what should I have done if you hadn't arrived just as you did? But how did you know where we were?"

"I didn't," said Stone; "it was Fibsy's idea that the man would take to the woods. But your screams and the noise of the revolver led us at the last. I congratulate you, Miss Clyde, on a pretty narrow escape. Those men were desperate."

"Oh, I know it! Pollock began by being fairly courteous, but when I wouldn't give up the pin, he grew rough and rude."

"Miss Clyde, we must look out for that pin. Though, now that the one who wants it is in safe-keeping himself, there's not so much danger. But he may have clever assistants. By the way, there's no doubt that this so-called Pollock is Charlie Young. Hughes is putting him through a third degree, and I think we need not concern ourselves about him just now. He won't escape from his present quarters easily."

"This child must go to bed now," said Lucille Darrel, with an affectionate glance at Iris. "She's had enough to upset any ordinary set of nerves, and she must rest."

"Yes, Miss Clyde, go now, and I think, if you leave the pin with me I'll keep it safely, and moreover, to-morrow morning, I'll tell you its secret."

"Oh, tell me now! Please do, Mr. Stone. What can it be that makes it a key to the jewels' hiding-place?"

"Not to-night. Indeed, I don't yet know its secret myself, but I hope to find it out. If I may, I'll stay alone in Mrs. Pell's sitting-room for a time, until I puzzle it out."

Iris reluctantly went off with Lucille, and the detective locked himself in the room where Mrs. Pell had met her tragic death.

He had, as his working implements, the pin, a strong magnifying glass, a thick pad of paper and a lead pencil.

As the first streaks of dawn began to show in the eastern heavens, Fleming Stone had, as results of his night's work, forty or fifty scribbled pages of the pad, all of which were in the waste basket, a small, remaining stub of lead pencil and the pin and the magnifying glass.

Also he had a heavy heart and a feeling of despair and dejection.

He went to his room for a few hours' sleep before breakfast time and when he met the family at table, he said shortly, "Finding a needle in a haystack is child's play compared to the task ahead of us."

He refused to explain until after breakfast, and then, Iris and Lucille went with him to the sitting room and the door was closed upon them. Fibsy was there, too, as the boy was never excluded from important conferences.

Stone locked the door, and then said, impressively, "The dime and pin bequeathed you by your aunt, Miss Clyde, form a far more valuable inheritance than any diamond pin I have ever seen. I congratulate you on the possession of the pin, and I ask you where the dime is."

"Gracious, I don't know," replied Iris. "I threw it out of the window the day I received it, and I've never thought of it since."

"The pin is a key to the hiding-place of the jewels, as I will explain fully in a few minutes," Stone proceeded, "but it may be necessary to recover the dime also, before we can utilize the information given us by the pin."

Iris looked bewildered, but repeated her statement as to the whereabouts of the dime.

"And again," Stone said, "the dime may be of no importance in the matter. I'm inclined to think it is not, because Pollock—or Young rather—made no effort to gain possession of the dime, did he?"

"No; I think not. That first day he called on me, as Mr. Pollock, and wanted the pin, I told him he might search the lawn for the dime if he chose, but I don't think he did so."

"I'll find the dime if it's out in the side yard," Fibsy volunteered.

"Now, I'll tell you what this pin is," resumed Stone, holding up the mysterious bit of brass. "It contains a cipher—a cryptogram."

"How can it?" asked Iris, blankly.

"On the head of this pin is engraved a series of letters which form a cipher message telling of the hiding-place of your aunt's jewels."

"On the head of that little pin! Impossible!"

"It does seem impossible, but I assure you that on the surface of the head of this pin there are thirty-nine letters, which, meaningless in themselves, form a cipher statement. If we can solve their message——"

"If we can!" cried Iris. "We must!"

"You bet Mr. Stone will work it out, if it's a cipher," Fibsy declared, looking with pride and confidence at his employer's face.

"Not so easy, Fibs," Stone returned. "It's a cryptogram which necessitates another bit of information, a keyword, before it can possibly be solved. By the way, Miss Clyde, that's what your aunt's diary means by its reference to the jewels being hidden in a crypt. If you read her diary carefully, you'll see that she very frequently abbreviates her words, not only Tues., for Tuesday, and Dec., for December, but other words, just as the whim took her. So, as we may conclude, the word crypt stands for cryptogram. And here's the cryptogram. Now, to explain this seemingly miraculous feat of engraving thirty-nine letters on the head of an ordinary pin, I'll say that it is not an unheard-of accomplishment. Several years ago, I saw on exhibition a pin with forty-five letters to it, and I have seen one or two other similar marvels. They are done, in every instance, by a most expert engraver, who has much time and infinite patience and capacity for carefulness. Indeed, it is an art all by itself, and I doubt if there are many people in the world who could accomplish it at all."

"Can you show them to me?" Iris asked, her eyes wide with wonder.

"Oh, yes, you can see them with this glass, though even with its aid you may have difficulty in making out the letters."

Iris looked long and carefully through the powerful lens, and finally declared that she could discern the letters, but could not read them clearly.

Stone passed the pin and glass to Miss Darrel, and continued, "I spent nearly the whole night over it. I have copied off the letters, so now, if the pin should be stolen, at least we have its secret. Though, I confess the secret is still a secret."

"Lemme see it," begged Fibsy, as Miss Darrel gave up the effort to make out the letters at all.

The younger eyes of the boy read them with comparative ease.

"O, I, N, V, L, D, L," he spelled out "Sounds like gibberish, but all ciphers do that—why, Mr. Stone, the letters are clear enough and you can read any cipher that ever was made up, I'll bet! You know, you first see what letter's used most, and that's E——"

"Hold on, Terence, not so fast. That's one kind of a cipher, to be sure. But this is another sort. These are the letters:

"O I N V L D L Q P S V T H P J R C R N O X X I V B A Y O D I J Y A W W K M E U

"There's no division into words, which, of course, makes it infinitely more difficult."

"Aunt Ursula was crazy over ciphers!" exclaimed Iris, "she was always making them up. But she always called them ciphers, never cryptograms, or perhaps I might have thought that crypt. was an abbreviation. But can't you guess it, Mr. Stone?"

"One doesn't guess ciphers, they must be solved. And this one is of that peculiar kind that needs an arbitrary keyword for its solution, without the knowledge of which there is little hope of ever getting the answer."

"And you give it up?"

"Oh, no, indeed? I shall solve it, but we must find the word we need to make it clear."