The boy wheeled. "Yes?"

"What are you doing?"

"No harm. Rishi only look at old house."

"I thought you were trying to get inside," Nancy said. "You have no right to do that, you know."

"Rishi think n.o.body care," the boy replied.

Nancy said no more. She and the other girls walked slowly around the house. The windows were placed so high above the ground it was impossible to see any of the interior.

"It's just an old, empty house, I guess," Bess remarked. "Let's go!"

The girls returned to the front of the building. Rishi had vanished.

"Where is he?" Nancy asked. "Do you suppose he dared to climb in that porch window?"

"Rishi had a mischievous look in his eye when he said he thought no one would care if he investigated," Bess reminded the others.

"He's probably inside," Nancy acknowledged.

The girls sat down under a tree to wait for him, but minutes elapsed and Rishi did not reappear. At length Nancy grew impatient.

"I'm going in there to get him! It's time we start for home."

She rose and walked briskly to the porch. Nancy knocked on the door but no one answered. Bess and George watched her raise the window and step through. Five minutes elapsed, then ten.

"What can be keeping Nancy?" George asked. "I think it's time I go after her. Want to come along?"

"I'll wait here. But let me know if there's anything interesting inside."

"I'll return soon," George promised.

Ten minutes later, Bess became convinced that something was wrong. Hurrying toward the house she called loudly, "George! Nancy!"

Her cries went unanswered. A sudden fear gripped Bess. She was certain that Rishi and her friends were being held prisoners inside the old house. If she were to enter, she too might be captured!

CHAPTER V.

Hidden Rock Door "I'LL go for help!" Bess decided.

Almost overcome with fear and anxiety, she raced down the trail toward Nancy's convertible. Once she stumbled and fell headlong, tearing her slacks. She scrambled to her feet and ran on again.

Reaching the car, Bess was relieved to find that Nancy had left her keys in the usual hidding place. Bess started the motor.

"Where shall I go?" Bess wondered, starting to panic. She recalled having seen a farmhouse at the end of a nearby lane and decided to drive there for aid.

In her excitement Bess stepped too hard on the gas pedal and the car leaped ahead with a jerk, which flung her against the wheel. She slowed down. The road twisted and turned in a bewildering maze and seemed to lead into even wilder country. To the right, a short distance from the road, a high cliff of boulders and jagged rocks loomed up.

For an instant Bess's attention was fixed on the unusual formation. Then she stiffened, uttering a sharp, terrified scream. Her imagination evidently had not tricked her into believing that the center of one boulder had moved.

"It's a man-made door hewn in the solid rock," she thought, hardly daring to believe what she saw as the rock was slowly swung outward.

Intent on the strange sight, Bess suddenly lost control of the steering wheel. The car careened wildly in the road, then pitched heavily into a rain-gutted ditch.

The impact momentarily stunned the girl, but she recovered quickly and was relieved to discover that the car still stood on its four wheels, apparently undamaged.

A moment later Bess cried out, "Oh-the cliff! A boy's coming out of it!"

He emerged hastily and pushed the rock door back in place. He ran down the steep embankment toward the girl.

"Rishi!" Bess screamed, and then laughed in relief. "For an instant I thought you were a ghost!"

"Rishi no ghost. Very much real."

"You nearly made me kill myself."

"Rishi sorry," the boy murmured contritely. "You not hurt?"

"No, I'm all right, thank goodness. But I wonder if I'll ever be able to get Nancy's car out of this ditch?"

"Rishi push and it be all right, I think." He ran to the rear of the car but Bess stopped him in his tracks.

"First tell me if I'm dreaming," she said. "Did I actually see you come through a rock door in that cliff?"

Rishi nodded, politely waiting for another question from the girl before revealing any more information.

"But you were investigating that old place when I saw you last!" Bess exclaimed in bewilderment. "How did you get here? And what became of Nancy and George?"

"Rishi see no one in tunnel."

"You've been exploring a secret tunnel?" Bess demanded eagerly. "Does it lead from the abandoned house?"

Again the boy nodded. His brown eyes danced with excitement as he tried to explain.

"Rishi step through window in strange house. House have no insides."

"No insides? What do you mean?"

Rishi seemed unable to make himself understood. He groped for words.

"You mean it had no floor-no furniture?" Bess suggested.

"Yes, no floor, no insides! Steps lead down into blackness. Then Rishi fall. Find himself at bottom of stone stairs. Long tunnel lead here. See light through crack. Push rock away."

"The rock!" Bess cried out. "A boy's coming out of it!"

Bess was bewildered by the boy's story, but thought his adventure offered a clue to the whereabouts of Nancy and George. Either in descending the stone stairway they had met with a mishap similar to Rishi's, or they had remained in the tunnel to investigate. Aware of Nancy's love for mystery, Bess was inclined to favor the latter theory.

"George and Nancy must be in the tunnel or the house," she declared. "Come, Rishi, show me how to enter through the rock."

Obediently he led the way up the steep bank to the boulder. He slipped his fingers into a crevice and pulled with all his strength. The rock did not move.

"Strange," he muttered. "Most strange. Rock move easy when Rishi push from other side." He tried again.

"Let me help," Bess offered.

Although the two pulled hard, it was impossible to budge the boulder even an inch. The secret door remained firmly in place.

"It's no use," Bess said in disappointment, giving up her efforts and resting. "We must return to the abandoned house."

Rishi hesitated, apparently afraid of risking further bruises.

"Nancy and George may be in serious trouble," Bess said urgently.

"Then Rishi go with you," the boy promised quickly. "But Rishi enter house in more safe way."

They returned to the car. Bess started the engine and shifted into low gear while Rishi pushed the convertible from the rear. The ditch was not deep, and with a low, rumbling protest, its wheels spinning in the dirt, the car lurched onto the road again. Rishi sprang inside, and Bess drove to the spot where Nancy had left the car before.

She and Rishi got out and ran along the twisting trail to the deserted house. In her anxiety to reach Nancy and George, Bess did not notice that Rishi was lagging farther and farther behind. Half walking and half running, she reached the place ahead of him and waited impatiently by the porch.

"Hurry, Rishi!" she urged, trying to catch her breath.

The boy eyed the building with obvious misgivings. "No need to go inside," he announced evenly.

"Nancy and George may be in serious trouble!"

"Not while Nancy wear wonderful elephant charm. If she meet bad trouble mystic power of charm save her."

Rishi spoke with a conviction that Bess could not share. She was provoked by the boy's att.i.tude, sincere though it might be.

"Oh, Rishi, you place too much trust in that ivory piece! I can't believe it has any unusual powers!"

"Ivory charm never fail," the boy insisted.

Bess was so exasperated, she felt like crying. She knew it would be impossible now to induce Rishi to reenter the strange house. She must investigate herself. But Bess, always more timid than her friends, was afraid to go in alone.

She stared at the building in a torment of indecision. Suddenly from far away she heard a cry.

"What was that?" she asked sharply.

The call was repeated. Bess thought she heard her own name.

With Rishi close behind, she ran toward the sound. Rounding an abrupt turn in the path, Bess nearly collided with Nancy. The girl's clothes were torn, her face was streaked with dirt, and her arm was bleeding from a scratch.

"Nancy!" Bess cried. "You're hurt!"

"You cut!" Rishi added.

"I'm all right." Nancy smiled. "But I've certainly had a strange experience."

"What became of George?" Bess asked.

"Isn't she with you?"

"No, When you failed to return she followed you into the abandoned house. I haven't seen her since."

"Then she must be somewhere in that wild labyrinth," Nancy answered, looking troubled. "I thought I'd never find the way out myself. My flashlight smashed when I fell. I kept walking and stumbling in the dark until I came to a queer door in a rock. It sounds impossible but it's true."

"I know it is," Bess said, "because I saw Rishi come out of that same boulder. He's been telling me a strange tale about the house having no in sides."

The boy's eyes were glued on Nancy, waiting for her to answer.

"That's true, too," Nancy declared. "It's the weirdest, most fantastic place I've ever seen. Only I didn't see too much of it! It was almost pitch-black."

"George must be lost somewhere in the tunnel you and Rishi were in, Nancy."

"I'm afraid of that, Bess. We'll have to go inside and search for her."

"But we have no light," Bess reminded her. "If you and Rishi could find your way out, I'm sure George could."

Nancy agreed to wait a little longer. "Probably the wisest thing to do is to return to the boulder," she said after a moment's pause. "George could escape that way eventually and come back to the house."

Hastily the three returned to the exit of the tunnel and began their vigil. First, however, Nancy convinced herself that Bess and Rishi were correct in saying that the mysterious door could not be opened from the outside.

Minutes elapsed and the lost girl did not appear. Bess and Nancy grew more worried, especially when they noticed that the sky was overcast with black, rolling clouds.

"Bad storm come," Rishi predicted.

"And it will soon be here," Nancy agreed. "I believe it's useless to wait any longer. Let's go back to the house and enter through the window."

Once more the three retraced their steps down the road and along the forest trail, coming at last within view of the abandoned house. In the gathering darkness it looked even more sinister and forbidding than it had before.

"I don't like the idea of going inside." Bess shivered.

"Neither do I," Nancy admitted, "but we must find George."

She moved boldly toward the front porch, with Bess and Rishi following reluctantly. Nancy paused to listen intently.

"It was only thunder," Bess said.

"No, I heard something-"