She was momentarily stunned. Then, realizing that she was trapped in a burning building, she struggled desperately to free herself. She kicked with all her strength against the floor and walls of the closet.

Finally, she succeeded in loosening her gag.

"Help! Help!" she screamed.

Her voice sounded m.u.f.fled and weak. The top floor was without tenants, and Penny knew that the chance of anyone hearing her was very slight.

She was doomed to a horrible fate.

Her courage failed her for the moment and she sobbed in terror. But she soon had herself in check again and was struggling to free herself.

It seemed to her that the cords which held her wrists were a trifle looser--she worked at the knots with her teeth.

From below she heard a loud clanging, and the shrill whistle of a fire siren. New hope surged over her. Perhaps the firemen who had arrived upon the scene would reach her in time!

"Even if they shoot a ladder up to the window they'll never think anyone could be tied up in the closet," she reasoned. "If I'm to escape, it will be from my own efforts."

Penny knew that the fire was rapidly spreading, for she could hear a steady roar which rapidly grew louder. The closet was so warm that she found difficulty in breathing. She could plainly smell smoke.

Then suddenly, almost when she had given up hope, she was free. Her wrists were bruised and bleeding but that was of no consequence. It required only an instant to untie the cords which bound her ankles.

A new fear a.s.sailed her. The closet door might be locked!

She turned the k.n.o.b and laughed aloud in hysterical relief. It had not been locked. But as she darted out into the room she inhaled smoke-laden air and began to cough and choke. Covering her face with her dress, she groped her way to the door.

It did not give as she tried it. Then she remembered that Cron and his confederates had locked it from the outside.

She threw herself against the wooden panels with all her strength, but quickly comprehended that she could not break them. She ran to the window and looked down.

Smoke was swirling upward in such large black clouds that she caught only an indistinct view of the street below. The big red fire engine had pulled up beside the building and rubber-coated men were squirting streams of water on the roaring blaze.

Penny lifted the window sill and climbed out on the ledge. She clung there, waving one hand to attract attention to her plight.

Below, when the smoke cleared a little, she could see a solid bank of spectators, edged off neatly by a cordon of police. Others were trying to push their way through the crowd. A great clanging of bells announced the arrival of another fire company. It pulled in alongside the one already on the job.

With the precision of a war machine, the newcomers drove into action.

A hydrant was quickly tapped and a long reel of hose swiftly unwound and connected. A water tower arose from the ground as if by magic, and soon a great stream was pouring from its peak into the blazing building.

Penny shouted for help, although she knew her voice would not carry above the roar of the flames. Then as she was beginning to despair, she was seen.

With quick discipline, the firemen placed a ladder directly beneath the window. Slowly it arose, section on section.

Now that rescue was in sight, Penny suddenly vanished through the window back into the room from which she had escaped. The crowd below groaned in unison, fearing that the girl had lost her courage and was afraid to descend the ladder from such a height.

But Penny quickly reappeared at the window, bearing two bulky objects in her arms. She had determined to save the stolen Rembrandt and one of the copies which would serve as damaging evidence against Cron and his confederates.

A fireman swiftly mounted the ladder to help the girl descend.

"You'll have to leave those pictures," he said tersely. "This wall is about ready to fall and we have to work fast."

"I can't leave them behind," Penny wailed. "This one painting is worth thousands of dollars!"

"Then give them to me," the fireman ordered tersely.

He helped Penny step from the ledge to the ladder.

"Don't look down," he commanded.

Penny gripped the sides of the ladder, descending very slowly, with the fireman just below to steady her should she grow dizzy. She was not afraid although the ladder weaved under her weight. Even when a cloud of dense smoke caused her to choke and cough, she did not falter.

As the ground loomed up, she glanced back at the window ledge where she had clung only a moment before. Flames were shooting out, licking greedily at the top rungs of the ladder.

A great shout went up from the crowd as Penny stepped to the ground uninjured.

"Here you are, Miss, safe and sound," the fireman said grimly. "And just in time too!"

Scarcely had the ladders been removed from the building when the wall fell inward. Penny did not speak for a minute. Now that it was all over, she felt weak and shaken. Her escape had been such a narrow one.

"Are you all right?" the fireman asked, taking her arm.

"Quite," Penny smiled. "You needn't hold me. I'll not faint."

"You have pluck, Miss. And your wrists are cut too. I'll call the doctor."

"No, don't bother. It's nothing," Penny protested. "Where are my pictures?"

"Here." The fireman handed them over to her. "It was foolish going back after them. You might have lost your life."

"I realize that now," Penny responded soberly, "but I just had to get those pictures. Thank you for helping me save them."

Before she could add that she felt deeply grateful for her own rescue as well, the fireman was called to another post.

With a policeman as a bodyguard, Penny pushed her way through the crowd, the precious Rembrandt and the duplicate clutched under her arm.

"I'll send you to the hospital where you can have those wrists properly dressed," the policeman said. "How did you cut them?"

"Trying to get out of the closet," Penny answered. "I was bound and gagged and locked in."

Tersely, in response to the officer's questions, she related her terrifying experience in the studio, and displayed the paintings as evidence of the plot in which Cron and his friends were involved.

"If the police go to Cron's studio right away they may be able to capture the entire gang," she finished. "But there's not a second to lose!"

"Leave it to me," the policeman a.s.sured her grimly.

He communicated with headquarters and in an incredibly short time a squad car picked up Penny and the officer, driving with all speed toward the studio of Hanley Cron.

CHAPTER XX

The Secret Revealed