The foreman’s eyes seemed to glow in the dark. “Indians always did say that no one could see
Mr. Dalton frowned. “Investigators, eh? Well, I don’t know, boys. The sheriff might not like boys interfering.”
Professor Walsh looked at the card. “Why the question marks, boys? Do you doubt your ability as detectives?”
The professor smiled at his own joke, but Bob and Pete only grinned and waited for Jupe to explain. Adults always asked about the question marks, which was exactly what Jupiter wanted.
“No, sir,” Jupiter said. “The question marks are our symbol. They stand for questions unanswered, mysteries unsolved, enigmas of all sorts that we attempt to unravel. So far we have never failed to explain any riddle we’ve found.”
Jupiter said the last proudly. But Mr. Dalton was looking at the second card, a small green one. Each of the boys had one, and they all read the same:
“You boys certainly showed more sense to-night than half the adults around here,” Mr. Dalton said at last. “Maybe three boys with a fresh viewpoint are just what we need to solve this nonsense. I’m sure there’s a simple explanation, and if you promise to be very careful around that cave, I say go ahead and investigate.”
“We’ll be careful!” the boys cried in unison.
Mrs. Dalton smiled. “I’m sure there’s some very simple explanation we’ve all missed.”
Mr. Dalton snorted. “I say it’s the wind blowing through those old tunnels and nothing more.”
Jupiter finished the last cookie. “You and the sheriff have searched the cave, sir?”
“From one end to the other. Many of the passages are blocked by debris from old earthquakes, but we searched every one we could find.”
“Did you find anything that looked as if it had changed recently?” Jupiter questioned.
“Changed?” Mr. Dalton frowned. “Nothing we could see. What are you getting at, son?”
“Well, sir,” Jupiter explained, “I understand that the moaning only began a month ago. Before that it hadn’t been heard for at least fifty years. If the wind is causing the sound, then it seems only logical that something must have changed inside the cave to make the moaning sound start again. I mean, I doubt if the wind has changed.”
“Hah!” Professor Walsh said. “There’s clear logic, Dalton. Perhaps these boys can solve your mystery.”
Jupiter ignored the interruption. “I also understand,” he went on, “that the moaning occurs only at night, which would not be the case if the wind alone were responsible. Have you noticed if it happens every windy night, by any chance?”
“No, I don’t think it does, Jupiter,” Mr. Dalton was beginning to look really interested. “I see what you mean. If it were just the wind, then we should hear moaning every windy night… Of course, it could be a combination of wind and some special atmospheric condition.”
Professor Walsh smiled. “Or it could be El Diablo, come back to ride again!”
Pete gulped. “Don’t say that, Professor. Jupe already said the same thing!”
Professor Walsh looked over at Jupiter. “He did, did he? You’re not going to tell me that you believe in ghosts, are you, young man?”
“No one knows about ghosts for sure, sir,” Bob put in seriously. “However, we’ve never actually found a real ghost.”
“I see,” the professor said. “Well, the Spanish people have always insisted that El Diablo will come back when he is needed. I’ve done a great deal of research, and I can’t really say that he couldn’t come back.”
“Research?” Bob asked.
“Professor Walsh is a professor of history,” Mrs. Dalton explained. “He’s here in Santa Carla for a year to do special research on California history. Mr. Dalton thought he might be able to help us explain Moaning Valley to our ranch hands.”
“With no luck so far,” the professor admitted. “But perhaps you boys would be interested in the full story of El Diablo? I’m thinking of writing a book on his colourful career.”
“That would be great!” Bob exclaimed.