Freddie Bobbsey sat down with a thump. Flossie Bobbsey sat down with a bump. This was after they had fallen down the queer hole. And yet it had not been so much of a fall as it was a slide.

Both of them being fat and plump—much fatter and plumper since they had come to Twin Camp than before—the thump and the bump did not hurt them very much.

They had slid down into the hole on a sort of hill of sand, and if you have ever slid down a sandy hillside you know the stopping part doesn't hurt very much. And, after all, the part of a fall that hurts, as the Irishman said, is not really the falling, it's the stopping so suddenly that causes the pain.

"Freddie! Freddie!" called Flossie, a few seconds after she and her little brother had fallen down the hole. "Freddie, are you there?"

"Yep, I'm here, Flossie," was Freddie's answer, "only I dunno 'xactly where it is. I can't see."

"Nor me neither. But are you been hurted, Freddie?"

"No, are you?"

The children were forgetting all about the right way to use words, which their mother had so often told them, but as they were excited, and a little frightened, perhaps we must excuse them this time.

"I—I just sort of—of bumped myself, Flossie," said Freddie. "Are you all right? And where are you?"

"I'm right here," replied the little girl, "but I can't see you. I—I——It's awful dark, Freddie!"

"I can see a little light now," Freddie went on. "Let's get up and see if we can crawl back. My legs are all right."

"So's mine, Freddie. I guess I can——" and then Flossie suddenly stopped and gave a scream.

"What's the matter?" asked Freddie, and the little boy's voice was not quite steady.

"I—I touched something!" gasped his sister. "It was something soft and fuzzy."

"Oh, was that you?" asked Freddie, and his voice did not sound so frightened now. "Well, that was my head you touched. I—I thought maybe it was something—something after me. I didn't know you were so close to me, Flossie."

"I didn't either. But I'm glad I touched you. Where's your hand. I'm sort of stuck in this sand and I can't get up."

By this time the eyes of both the children had become more used to the darkness of the place into which they had fallen, and they could dimly see one another. Freddie scrambled to his feet, shaking from his waist and trousers the sand that had partly filled them when he had slid down the incline, and gave his hand to Flossie. She had about as much sand inside her clothes as he had, and she shook this out. Both children then turned and looked up at the slide down which they had so suddenly fallen.

Up at the top—and very far up it seemed to them—they could see, at the end of the sandy slide where they had started to slip, a hole through which they had fallen. It was between two big stones, and had a large bush on either side. It had been covered with grass and bushes so that the small twins had not seen it until they stepped right into it. Then the grass and bushes had given way, letting the children down.

"We—we've got to get back up there—somehow," said Freddie with a doleful sigh, as he looked at the place down which he and his sister had tumbled.

"Yes, I would like to get up out of here," said Flossie, "but how can we, Freddie?"

"Climb up, same as we falled down. Come on."

Taking his sister by the hand, Freddie started to climb up the hill of sand. But he and Flossie soon found that though it was easy enough to slide down, it was not so easy to climb back. The sand slipped from under their feet, and even though they tried to go up on their hands and knees it was not to be done.

"Oh, dear!" cried Flossie after a while, "I wish we were Jack and Jill."

"Why?" asked Freddie.

"'Cause they went up a hill, an' we can't."

"Maybe we can if we try again," said Freddie. "Anyhow, I don't want to be Jack, and fall down and break my crown."

"You haven't any crown," said Flossie. "Only kings an'—an' fairies have crowns."

"Well, it says in the book that Jack has a crown; an' if I was Jack I'd have one too. Only I'm not and I'm glad!"

"Well, I wish I was Jill, so I could have some of that pail of water," sighed Flossie. "I'm firsty," and she laughed as she used the word she used to say when she was a baby.

"So'm I," said Freddie. "Let's try to get up to the top, an' then we can get a drink, maybe. Only I'd rather be Ali Baba than Jack, then I could say, 'Open Sesame,' and the door to the cave would open of itself, and we could walk out and carry diamonds and gold with us."

"I'd rather have bread and butter than gold. I'm hungry. And I'd most rather have a drink," sighed the little girl. "Come on, Freddie, let's try to get up that hill. But it's awful hard work."

"Yes, it's hard," agreed Freddie; "but we've done lots harder things than that." You see, Freddie was trying to keep up his little sister's courage.

Once more the two little twins tried to climb the hill of shifting sand, but they could get up only a little way before slipping back. They did not get hurt—the sand was too soft and slippery for that, but they were tired and hot, and, oh! so thirsty.

"I'm not goin' to climb any more!" finally said Flossie. "I'm tired! I'm goin' to stay here until mamma or papa or Nan or Bert comes for us."

"Maybe they won't come," Freddie said.

"Yes, they will," declared Flossie, shaking her head. "They allers comes when we're lost and we're losted now."

"Yes, I guess so," agreed Freddie. "I wonder where we are anyhow, Flossie?"

"Why, in a big hole," she said. "Oh, Freddie!" she suddenly cried, "maybe we can get out the other way if we can't climb up."

"Which other way?" asked her brother.

"Out there," and in the light that came down the hole through which the twins had fallen Freddie could see his sister pointing to what seemed another dim light, far away at the end of the big hole. For Flossie and Freddie had fallen into a big hole—there was no doubt of that. Though it was pretty dark all about them, there was enough light for them to see that they were in a cavern.

"Maybe it's a cave, like the one we went into from the lake when we found the boat," said Flossie, after thinking it over a bit, "and if we can't get out one end we can the other."

"Maybe!" cried Freddie eagerly. "Anyway, we can't get up that hill of sand," and he pointed to the one down which they had slid. "Come on, we'll walk toward the other light."

Far away, through what seemed a long lane of blackness, there was a dim light, like some big star, and toward this, hoping it would lead to a hole through which they could get out, the children walked.

As they neared it the light grew brighter, and they were beginning to feel that their troubles were over when suddenly they both came to a stop.

For, at the same time, they had heard a queer noise. It came from the darkness just ahead of them and was such a funny sound that Flossie put both her arms around Freddie, not so much to take care of him as that she wanted him to take care of her.

"Did—did you hear that?" she whispered.

Freddie nodded his head, and then, remembering that Flossie could not very well see his motions in the darkness he said:

"Yes, I heard it. I wonder——"

"Hark!" whispered Flossie. "There it goes again!"