For a time the three stood regarding one another with startled eyes. Then Arthur gasped: “Great heaven! what fools we’ve been.”

“Come!” cried Patsy. “The nursery.”

They rushed down the corridors to the staircase and thence into the court. The door of the nursery stood ajar and Arthur first entered and lighted a lamp.

The light fell full upon the face of a man seated in a low rocking chair and holding a half smoked cigarette in his mouth. He was fast asleep. It was old Miguel, the ranchero.

Arthur shook his shoulder, savagely, and the man wakened and rubbed his eyes. Then, seeing who had disturbed him, he quickly rose and made his characteristic low, sweeping bow.

“What are you doing here?” demanded Weldon, angry and suspicious.

“I am look for Mees Jane,” returned the old man calmly.

“In your sleep? Come, get out of here.”

“Wait a minute, Arthur,” said Beth, reading Miguel’s face. “He knows something.”

Arthur looked at the man critically, reflecting that there must be a reason for his presence in the nursery. Miguel had been fond of baby Jane. Was he merely disconsolate over her loss, or—did he really “know something”?

“Miguel once told me,” said Patsy, speaking slowly, “that he used to live in this house, in Cristoval’s time, and knows it thoroughly.”

The old man bowed.

“I theenk,” said he, “perhaps we find Mees Jane here—not somewhere else.”

“Why do you think that, Miguel?”

It was Patsy who questioned him. He mused a bit before replying.

“The old seÑor—the father of my SeÑor Cristoval—was strange mans,” said he. “He make thees house a funny way. Come; I show you.”

He led the way to the little room adjoining, the one Inez had occupied. In one corner of the floor was a square hole, with steps leading down to a sort of blind pocket. Holding a lamp in one hand Miguel descended the steps and pushed against a block of adobe that formed part of the outer wall. It swung inward, disclosing a cavity about four feet in width and fully six feet high. The interior could be plainly seen from the room, by stooping close to the floor. There were shelves in the cavity and upon one of them stood a jar of milk.

“Oh,” cried Patsy, clasping her hands together. “I told you the wall was hollow!”

Arthur followed Miguel down the steps. He took the lamp and examined the little room. All the walls that formed it seemed solid.

Miguel was holding the block that served as a door. He released his hold, when Arthur had again ascended, and the block swung back into place.

As they returned to the nursery, Weldon asked:

“Do you know of any other rooms in the wall, Miguel?”

The man shook his head, uncertainly.

“I know there be other rooms in thees wall,” said he, “for SeÑor Cristoval have told me so. Hees father make the places to keep things safe from robbers—perhaps to hide from others, too. But where such places are ees the secret of the Cristovals. The room I show you ees all I know about. I thought that was secret, too; but no; the New York nurse tell Inez of that room, an’ Inez she keep Mees Jane’s milk there, to be cool.”

“Mildred told of the room!” exclaimed Arthur in astonishment.

“Yes,” said Beth, “she used to visit this house as a girl, when Cristoval lived here, and she must have known some of the secret rooms.”

“Ah, that ees what I theenk,” agreed old Miguel. “There ees more room in thees wall; that I know. If thees Mildreed know one room, she may know more. So I theenk she and Inez have go into some room of the wall an’ take Mees Jane with them. Some way, they cannot get out again.”

“Exactly!” cried Patsy triumphantly. “They are somewhere in that wall, imprisoned, and the major really heard the baby cry.”

“But—Miguel, Miguel!” pleaded Arthur, earnestly, “can’t you remember how the wall opens? Think! Think carefully.”

“I do theenk, Meest Weld; I theenk till I go sleep, an’ you find me here.”

“Now, let’s do some thinking ourselves,” suggested Beth. “The opening that leads into the wall must be from this very room. Miguel thinks so, too, and that’s why he came here. Let us examine the wall.”

They undertook to do this, holding the lamps close to the adobe blocks and inspecting every crack. The cement used in joining the blocks had crumbled away at the outer edges in almost every instance, and it was impossible to tell if any block was removable or not. Miguel or Arthur pushed hard against every block in the room, from those nearest the floor to those far above their heads; but not one yielded a hair’s breadth.

“Suppose we go outside,” said Patsy. “Perhaps there is some window, or grating, that will give us a clue.”

So they took old Miguel’s lantern and went into the garden where they could view the outer side of the wall. A tangle of climbing vines grew against the wing, but there was no window or other opening on the first floor. Above, on the second floor, were two windows, one of which admitted light and air to the blue room.

“How about the other window?” asked Beth.

“That,” said Arthur, “must be in an unused room at the end of the corridor. We have never furnished it.”

“I think it might be well to examine that room,” suggested Patsy.

So they reentered the house and, followed by Miguel, ascended to the second floor. The door of the library was ajar and those seated there, seeing Arthur and the girls pass, came trooping out to ask what they were doing.

Patsy briefly explained the new theory they had conceived to account for the disappearance of baby and the two nurses, and the idea was so startling that all became eager to join in the investigation.

They invaded the vacant room in a body, several of the men carrying lamps. It was in size and shape a duplicate of the blue room, with its one window deeply embedded in the wall, the surface of the embrasure being covered with heavy redwood planks.

From the fact that this room lay directly over the small one occupied by Inez, in which was the wall cavity they had recently explored, they conceived the idea that the wall here might also be hollow. Pounding upon it, however, had no effect in determining this, for kiln-baked adobe is not resonant and it was impossible to discover from any surface indication whether there were eight feet of closely set blocks or less. Careful search for any sign of an opening proved futile.

Finally old Miguel said:

“Next room was room of SeÑor Cristoval. Eet was room hees father live in, too; the old seÑor who build thees part of house. If there ees way to get in wall, from upstairs, it ees there.”

“To be sure,” said practical Beth, catching at the suggestion; “it was there that Major Doyle heard the baby cry.”

So on they all trooped into the blue room, where the wall was likewise carefully inspected. While this was being done Rudolph looked at his watch and found it was after four o’clock.

“It will soon be daylight,” said he to his wife. “What a night it has been! It seems a month since we arrived here and found Toodlums gone.”

Old Miguel had been silent and unobtrusive in the vacant room, but here he was as eager in testing the wall as any one of them.

“You see, it’s this way,” Patsy was saying; “if the major could hear baby cry, through this wall, those inside could hear us, if we called to them. Who among us has the clearest, the most penetrating voice?”

“Suppose I try?” squeaked Runyon, earnestly; but those who considered the remark at all merely gave him scornful looks.

“Let Rudolph call,” said Helen. “I think his voice might penetrate the pyramids of Egypt.”

Rudolph went close to the wall and shouted:

“Hello, there! Baby! I-nez!—eh—eh—what’s the other girl’s name?”

“Mildred,” said Beth.

“Mil-dred!” shouted Dolph; “Mil-dred!”

He paused between each name, which he roared so loudly that he nearly deafened those in the room, and everyone listened intently for a response.

No answer.

“Perhaps they’re asleep—worn out,” said Uncle John. No one now seemed to doubt that the missing ones were imprisoned in the wall.

“Let Beth try,” suggested Patsy.

Beth had a clear, bell-like voice and from where she stood she called out the names of Inez and Mildred. Then, in the stillness that followed, came a muffled cry in return—a cry that set all their nerves quivering with excitement.

The mystery was solved at last.

Beth repeated the call and now the answer was clearer, though still indistinguishable. It was a voice, indeed, but whose voice they could not tell. But now, to their astonishment, came another sound, quite clear and distinct—the wail of a baby voice.

“That settles it!” cried the major, triumphantly. “Was I right, or wrong? Was it a nightmare, or was I crazy?”

“Neither one, my dear sir,” replied the doctor. “You declared you heard a ghost.”

Arthur was capering about in frantic joy.

“She’s alive—my baby is alive!” he exclaimed.

“And probably she was sound asleep until your infernal yelling awakened her,” added the major.

“It wasn’t our yelling,” said Uncle John, as delighted as even the father could be; “it was the yelling of whoever is inside, there, that frightened the baby. Thank goodness the dear child could sleep during all these weary hours, when we have been wearing our hearts out with anxiety.”

“We have yet cause for anxiety,” declared Patsy, “for little Jane is not rescued yet, by any means, and presently the poor thing will become very hungry and suffer for lack of food. We now know where baby is, but we can’t get at her; nor can Mildred or Inez find a way to get her out, or they would have done so long ago.”

“Very true,” agreed Helen Hahn, gravely. “Unless we can soon find a way to get to them, all three will starve.”

“Why, we will pull down the wall!” cried Arthur.

“Dynamite it!” piped Bul Run.

“Be sensible!” counseled Uncle John sternly. “We are wasting precious time. Miguel,” turning to the ranchero, “get some of your men, with picks and crowbars, and fetch them here quickly.”

The Mexican, who seemed bewildered by the discovery of the missing ones, although he had himself been the first to suspect where they were, started at once to obey this order. When he had gone, Patsy said:

“Of course there is some easy way to get inside the wall, and to get out again. Are we so stupid that none of us can penetrate the secret of the cunning Spaniard who built this place?”

The challenge merely led them to regard one another with perplexed looks.

“The fact that they’re alive, after all these hours,” said young Hahn, “is proof that they are supplied with air, and plenty of it. Then there is an opening, somewhere or other.”

“Also,” added Arthur, reflectively, “they are now opposite the second story rooms, when they must have entered the hollow wall at the first floor—perhaps from the nursery. That proves there is a stairway, or at least a ladder, inside.”

At this moment a maid entered to say that Mrs. Weldon had awakened and was calling hysterically for her baby. The doctor and Patsy at once hurried to Louise’s bedside, where the girl said:

“Don’t worry, dear. Little Jane has been found and is now in this very house. So try to be quiet and go to sleep again.”

“Bring her to me; bring my darling at once!” begged Louise. But the doctor now interfered.

“I don’t wish to disturb baby at present,” he said positively. “I think the child is sleeping. You have been quite ill, Mrs. Weldon, and I must insist on your remaining quiet. Here; drink this, if you please.”

Louise, reassured, drank the potion and presently sank into another doze. Dr. Knox remained beside her for a time but Patsy hurried back to the blue room, eager to assist in the rescue of the prisoners.

“I’m afraid we’re a stupid lot,” Uncle John was saying as she entered; “or else the Spanish don was remarkably clever. We know the wall is hollow, and we know there’s an opening, yet we can’t solve the riddle.”

But here came Miguel and two strong men laden with steel bars, cold chisels and picks. For a time it was a quandary where to attack the wall, but Arthur finally chose the place just back of the bed and bade the men begin their work.

The adobe proved harder than the hardest brick. Old Miguel knew that it must be broken away bit by bit, for he was not unacquainted with the material, yet even under his skillful direction the work progressed with aggravating slowness.

Daylight gradually crept into the room and rendered lamps unnecessary. The morning discovered a very disheveled, heavy-eyed group, not a single member of which was willing to retire from the fascinating scene of rescue.

Patsy went away to arouse Sing Fing and the servants, some of whom she found had remained awake all night. In half an hour steaming hot coffee was brought to the blue room and gratefully consumed by the weary watchers. Breakfast of a substantial character would soon be ready and it was agreed that part of them should eat at one time while the others remained to watch and to call them promptly if anything new developed.

Arthur, too nervous to stand idly by, insisted on attacking the wall in another place and Runyon assisted him, the latter’s strength and muscle winning the admiration of all observers. He worked fiercely for a time, driving in the bar with stalwart blows and chipping off huge pieces of adobe. Then, dripping with perspiration, he retired in favor of Arthur and rested by taking a seat in the window, where the cool morning air could fan him.

Patsy noticed Runyon in this position, his back against the redwood planks and his legs stretched out on the window-seat; but the work on the wall drew her attention, as it did that of everyone else.

Suddenly there was a crash and a loud report—followed by a shrill cry—and as every eye turned to the window they found that Runyon’s great body had absolutely disappeared. A rush was made to the window, but he did not seem to have fallen out. There was no sign of him at all. As if by magic, he was gone.

While they stood amazed and half frightened by the marvel of the thing, Patsy recovered sufficiently to say:

“Quick—let us get below! He must be under those rose vines, perhaps crushed and badly hurt.”

So they made for the door and flocked downstairs and out into the garden. The vines seemed undisturbed. When the men pushed them aside there was no evidence of the big rancher to be seen. In fact, they were all convinced that Runyon had not fallen out of the window.

Slowly they returned to the blue room, where the major exclaimed, with positive emphasis:

“This room is haunted. Don’t talk to me! There’s no other explanation. If we don’t watch out, we’ll all disappear—and that’ll be the end of us!”