"What happened to us?" Bess asked groggily.

"I think," said Nancy, "that our enemy put us to sleep with some sleeping gas he sprayed around."

"And the envelope!" George cried out. "Where is it?"

Nancy's listeners were stunned when she told them about Ross Monteith being there and the man with the scar on the back of his wrist having grabbed the envelope.

"The clue was in your grasp and they got it away!" Bess said woefully.

Ned arose and came to Nancy's side. "I feel mighty bad about this," he said. "I was just plain dumb not to think of our setting a guard. We laid ourselves wide open to an attack with all our lights turned on."

"Please don't blame yourself," Nancy said. By this time she felt that her mind was clicking almost normally again. "You know, it's just possible that those men did not get the clue after all."

"Whatever do you mean?" George asked.

Nancy reminded the others that there had been no name or anything else written on the envelope. "I admit I was getting pretty groggy at the time I was holding it, but the envelope didn't feel to me as though there was anything inside."

"You mean," said George, "that the real clue may be in one of the nine boxes we haven't uncovered yet?"

"That's right," Nancy answered. "But while we're looking, I think we should do what Ned suggested-set a guard. If there was nothing in that envelope we found, then those thieves will be back here to get the real one."

"More than that," said Ned, "I think the police should be notified. I'll drive to town and tell them while you continue the digging." He grinned. "And I'll bring you all some breakfast."

Nancy suggested that Ned also bring Art Warner, and told him where he could find the young lawyer.

The digging started again. Each chest was freed from the earth and quickly opened. The searchers looked for the elusive clue among the pieces of the stagecoach. Seven boxes had been opened and the eighth had just been raised when Ned Nickerson returned. With him were Art Warner, Sergeant Hurley, and Detective Takman.

"You're just in time to see the next to the last box opened," Nancy told them.

Everybody crowded around and Burt raised the lid. Inside the hand-wrought iron chest was the center seat of the old stagecoach. Nancy's quick eyes noted a small spot in the upholstery which looked as if it had been cut deliberately. Quickly she explored inside with her fingers.

"I feel something!" she cried out, and a moment later pulled an envelope from its hiding place. Smoothing it out, she read:TO THE CITIZENS OF FRANCISVILLE

"This is the real clue!" she exulted. Then she turned to Art Warner. "As a resident of that town, will you please open this and see what's inside?"

As everyone stood around in awe, the young lawyer carefully opened the envelope with his penknife and pulled out a letter. As he read it aloud, looks of delight spread over the faces of his audience.

The letter was signed by AbnerLangstreet and said that at the time the cornerstone of the town hall of Francisville was laid in the year 1851, Langstreet had been the person to put on the last bit of mortar to seal it. When no one was looking, he had slipped something inside the cornerstone box which he figured in years to come might be of great value to the town. He directed that when an emergency should arise, the cornerstone be opened and his gift used.

"How amazing!" Bess spoke up, as Art Warner stopped reading. "What's in the cornerstone?"

"The letter doesn't tell," the young lawyer replied. "But I should say that the time of emergency has arisen in Francisville. What do you all think?"

Everyone agreed with him and could hardly wait for the town fathers to open the cornerstone, so they might all see what the secret was.

"I'll arrange to have it done very soon, and we'll have a little celebration," Art Warner told the others.

George remarked, "And Mr. Langstreet's stagecoach belongs to the town too."

"Yes," said Nancy, then told the police officers and Art Warner that Mrs. Pauling had agreed to defray the expenses for having it fixed up.

Bess spoke up. "The old stagecoach should be put on display in Francisville-for a time at least, even if it's moved to Bridgeford later."

"What is to become of the stagecoach right now?" George asked. "We can't leave it here."

Art Warner had a suggestion. He said he had a radiotelephone in his car and would get in touch with John O'Brien. "I'll ask him to come and take these pieces to Mr. Jennings the carpenter."

Sergeant Hurley said that he and Detective Takman would stay there and guard the old stagecoach until John O'Brien arrived, then follow him to the carpenter's shop.

"And now let's have a celebration breakfast," said Ned. From the car he pulled out ham and egg sandwiches, thermos bottles of orange juice, and steaming cocoa.

When the orange juice was poured into paper cups, Ned raised his cup. "Here's to Nancy Drew, best girl detective in the world!"

"She's certainly amazing," Sergeant Hurley said.

Nancy thanked Ned for the toast, then said, smiling, "Sergeant Hurley, the whole story can't be told until you round up the suspects in the case."

"The captain was expecting some arrests at any moment when Takman and I left," the officer replied. "Why don't you ride into Francisville and stop at headquarters?"

"We'll do that," said Nancy.

The young people went directly there, while Art Warner said he would get in touch with the mayor and other officials to see about having the cornerstone opened very soon.

"Oh, I hope it will happen while I'm still at the lodge!" said Nancy.

The others waved good-by to the lawyer and walked into headquarters. Police Captain Dougherty was busy on the telephone. They waited for him to finish, then Nancy introduced herself and the rest of the group. She told him about the finding of the old stagecoach and the clue in it which might mean a great deal to the town of Francisville.

"You're just in time to hear some big news," he said. "My men are bringing in five prisoners. Mr. and Mrs. Monteith were finally located at a farm on the outskirts of the next town. Staying with them were the two thugs we've been trying to locate."

"And who's the fifth person?" Nancy asked.

"Judd Hillary. He'll have a lot of explaining to do."

The group arrived in a little while. Nancy and her friends were allowed to stay and listen to their confessions. Everyone of them glared darkly at the girl as if she had been personally responsible for their downfall. Ross Monteith's real name was found to be Frank Templer.

It was Judd Hillary who put the story together. He had a phobia against any changes in Francisville and the housing developments in particular, because his grandfather had told him valuable ore mines were under those very areas. Hillary had told this to the Monteiths and instantly Ross wanted to explore. It was his idea and Hillary's to try frightening people away.

The explosions had served a double purpose: one was to scare people into moving, the other to open any veins of ore. The actual dynamiting job had been given to the two thugs who proved to be amateurs at it and had nearly caused fatal accidents.

"Did you send Nancy to the deserted farmhouse at the time of the second explosion, hoping she would be injured?" George asked Ross Monteith belligerently.

Audrey spoke up vindictively. "Of course not. He just wanted to keep her in one spot while he was busy with his friends getting the dynamite ready for the explosion. But I wish to goodness something had happened!"

"That will be enough," said the police captain sternly. "I will take your testimony later."

The officer went on to say that before the hous. ing developments had been put up, every kind of test had been given to determine if there were any valuable mineral in that area. None had been found.