"Let me out of here!" the prisoner screamed.

Burt looked at Nancy who nodded, and the sack was taken from Crosson's head. Nancy thought she had never seen an angrier, more calculating smirk on anyone's face. The man's fiery red hair was sticking out in all directions. His eyes were like two gleaming coals, as hatred shone in them.

"Let me go!" he shouted.

Nancy looked at him and asked, "Where's Ned Nickerson?"

Instead of answering, Crosson cried out, "You'd better release me or you'll all die!"

Since the man was unable to use either his arms or legs, Nancy and Burt were sure that the threat was only an idle one. Nancy said she would go to the first floor and get Professor t.i.tus to identify Crosson. Upon hearing this, Crosson's eyes closed to a mere slit. Nancy thought he looked like a tiger about to spring upon its prey.

She hurried from the room and ran to the lobby. The scene before her startled the young detective. It was evident that Bess, George, Dave, and Professor t.i.tus had received a dose from the paralyzing searchlight. Fortunately they were all regaining their ability to move.

"Zapp Crosson is our prisoner in the attic!" Nancy exclaimed. "Professor t.i.tus, will you go up there with me to identify him?"

"Yea!" shouted Dave.

"Hypers!" George said. "You've done it again, Nancy Drew!"

The young detective still looked sober. "He won't answer my question about where Ned is, but I'm going back to see if I can find out anything." Then she asked, "Tell me exactly what happened down here."

Bess explained that she had seen the front door open silently and the red-haired Cyclops had come in with his paralyzing searchlight and immediately beamed it on Dave and her, but she had managed to scream. George and Professor t.i.tus had come running, and in turn had received an electrical shock.

Not only Professor t.i.tus, but Bess, George, and Dave accompanied Nancy to the attic. The professor took one look at the prisoner and said, "It's Zapp Crosson all right."

Then he glanced at the turned-off searchlight which was still lying on the floor. He picked it up and examined the strange gadget. It would no longer switch on and he declared that the mechanism had worn out.

Nancy went to stand in front of the prisoner. Again she asked, "Where's Ned Nickerson?"

Crosson eyed her skeptically. "Let me loose and I'll tell you a lot," he replied.

The others waited for him to give an explanation about the kidnapping. Instead he suddenly began to laugh.

"I know you're going to have me arrested but the authorities have no charge on which to hold me. You have no proof of anything. I had permission to stay in this museum and to work in this laboratory. That's not against the law. I'll deny everything else I'm accused of. That goes for your boy friend, Nancy Drew. I happen to know he's safe, but he'll never be able to leave the place where he's being held unless I give the word."

The red-haired man stopped speaking and refused to answer any further questions. When Nancy realized that for her to continue was hopeless, she decided to call the police and turn the whole matter over to them.

She hurried to the first floor and dialed the number. Tim Rooney answered.

"Don't tell me you've caught the intruder!" he said.

"Yes, I'm reporting just that," Nancy replied. "But he won't tell where Ned Nickerson is. Can some of your men come to the museum at once and take charge?"

"They'll be there shortly," Tim Rooney told her, then said how astounded he was that Nancy Drew had caught the kidnapper.

When two other officers arrived, they were equally amazed. Nancy led them at once to the third-floor laboratory. Crosson glared at the officers and instantly told the men that they had no case against him.

"I demand that you release me!" he said.

"There's already a warrant out for your arrest," one of the officers told him. "And if we need any proof, I think there are several witnesses right here in this room who will testify against you in court."

The men searched the prisoner's pockets. When they found nothing, they untied the electric cord which had bound him, slipped on handcuffs, and let Crosson stand.

"We'll lock him up," one officer said. Turning to Nancy, he asked, "Just how did you solve this case?"

"By two 1923 pennies," the young detective replied. Crosson gave a start and cast an ugly look in Nancy's direction.

The officer asked, "Where will I be able to find you people?"

Professor t.i.tus said he thought the group should return to Emerson at once for a good night's sleep. Everyone agreed and the police were given the telephone number of the fraternity house.

By the time they reached Emerson it was day-break. The whole group tumbled into bed, exhausted.

"What a day!" Bess said as she closed her eyes and trailed off to sleep.

George immediately followed her cousin, but after Nancy had relaxed for half an hour without dozing off, her mind began to race. She wished that Ned had been rescued instead of Crosson having been captured.

"We'll have to start another big search," she said to herself.

Presently the young detective became so restless she decided to get up, dress, and walk around the campus. Maybe a long stroll would help her figure out what her next move should be. She went outside and crossed the campus to a large playing field.

Hearing a noise above her, she looked up and saw a helicopter coming. As Nancy watched it, she was startled to see the craft pause directly overhead, then begin to descend.

Her heart pounding, she asked herself, "Is this the robot copter? And if so, why is it coming here?"

Suddenly it occurred to Nancy that one or more of Crosson's pals might be aboard! Should she run and avoid being captured?

The young detective was too intrigued to leave. The helicopter might contain another message from Ned!

CHAPTER XX.

Surprising Story

As the helicopter descended closer to Nancy, she became more and more tense. The craft settled to the ground.

The rotors slowed down and finally stopped. As Nancy stared, the door opened and the pilot jumped out. Suddenly Nancy caught her breath, then she started to run toward the young man as fast as she could.

"Ned! Ned! I can't believe it!" she cried out.

Realizing who she was, Ned too began to run. A few moments later they were in each other's arms.

"Oh, Nancy, I'm so glad you were the first one to greet me on my homecoming!"

"Ned, you're safe!" she exclaimed. This brought a twinkle to the good-looking young man's brown eyes. "There's so much to find out about where you've been," Nancy continued. "And how did you ever get away from where Crosson had hidden you?"

Ned looked at Nancy unbelievingly. "You found out who my abductor was?"