"I wonder why so many people came here in automobiles?" Joanne mused, as the girls walked off slowly.

"That's what I've been wondering," Nancy replied soberly, "but I think I might know."

"Why?" her friends demanded.

"It looks to me as if only a few persons are actually living in the Black Snake Colony. Apparently they want to give the impression that the organization is a large one, so they have these other people come the night set for the ceremonials."

"There were certainly a lot of men in those cars," added Bess.

"Why should they go to all that trouble?" Joanne asked doubtfully.

"I don't know," Nancy admitted, "unless it's because they're trying to hide something they're doing here." She changed the subject. "I think we'll be able to make costumes like theirs if you'll give us some old pillowcases and sheets, Jo. When we visit the cave, we must disguise ourselves to make our scheme work!

CHAPTER XIA Midnight Message

"When shall we visit the cave?" George asked.

"As soon as we can," Nancy answered. "Of course we must help Jo and her grandmother with the work."

Since there was no further evidence of activity on the hillside, the girls went to bed. The next morning George remarked, as she helped Nancy make her bed, "What do you suppose those men do between ceremonials? It certainly is strange how much time they spend in that cave!"

"What puzzles me is those automobiles that were on the hillside," Bess said. "Why did they come? Surely those men were here for something besides ballet dancing. What's your guess, Nancy?"

"I'm afraid I haven't any answer. But I mean to find one for Mrs. Byrd's and Jo's sakes."

The three girls learned that Reuben was due to be absent most of the day and offered to do his chores. During the morning they picked cherries and took them to town to sell at a local market. When they returned, a small, strange car was standing in the driveway. Loud voices were coming from the living room.