Doc gave them what information he had secured from the two prisoners.
"The two didn"t know what is behind this devilish gas business?" Renny demanded.
"They did not know," Doc said. "They did not know the truth about the ghosts, either."
"There"s an infernal mystery behind the gas," Renny grumbled. "That giggling ghost business is the most puzzling of all."
Doc Savage consulted a telephone directory. He found William Henry Hart listed in an apartment on Riverside Drive.
"Holy cow! Reckon Hart don"t live on his boat all the time," Renny rumbled.Because they might need more than one car before they were through, Doc and his aids took two machines for the short trip to Riverside Drive. Doc drove his coupe; the others rode in a sedan.
When the bronze man pulled to the curb in a side street near Riverside Drive, the other car drew up behind him, and Renny, Long Tom and Johnny came to Doc"s coupe.
"How we gonna work this?" Long Tom wanted to know.
"You wait here," Doc said.
The bronze man walked around the corner, found the number listed as William Henry Hart"s address.
It was a tall brick building, one of the most impressive on the Drive, where there were quite a few impressive buildings.
The sign said: APARTMENT HOTEL.
Doc Savage entered the building, went to the rental agent. Doc had little fear of being recognized, for he had not discarded his disguise.
"Penthouses?" the agent murmured.
"Yes. I"m interested in one," Doc said.
"I"m sorry. We have only one. It is rented."
"Is there any possibility of it being vacated soon?" Doc asked.
"I-ah-can"t say."
"If you will show me a floor plan of the penthouse," Doc said, "I might be interested in the future."
Any hotel, apartment or otherwise, likes to keep one hundred per cent rented. The proposal appealed to the rental agent.
"I have a floor plan!" he said quickly.
"Who is the present renter?" Doc asked.
"A man named William Henry Hart, a young inventor and manufacturer," the agent explained. "Here is the plan."
DOC SAVAGE took the penthouse layout and went back to his men. They got in the larger car to hold a consultation and examine the penthouse plan.
"This is gonna help," Long Tom grunted.
They saw the penthouse contained almost a dozen rooms, was actually on the roof of the hotel, with a terrace taking in all the rest of the rooftop.
"As a battlefield," Renny rumbled, "there"s plenty of room!"Long Tom said, "How"d they manage to get Monk, Ham and the girl up there secretly?"
Doc Savage pointed out the probable method. "Notice the private elevator. It does not open into the hotel lobby, but into a private hallway, with a side door, on the ground floor."
"They probably got lookouts all over the place!" Renny boomed.
"We will see."
Doc went to the side door which admitted to the private penthouse elevator hallway. He walked in nonchalantly, immediately stopped, and looked as confused and surprised as he could.
"Er-doesn"t this door lead to the hotel?" he said uncertainly.
"Naw!" said the man. "It don"t."
The man was built for guard duty. He had big hands, thick arms, sloping shoulders, and a scowl-ridden face. Also a natural look of suspicion.
From the ceiling, a flexible wire ran down to the man"s right fist; he was evidently holding a push b.u.t.ton on the end of the wire. He must have to hold it all the time he was standing there.
"This door is private!" he growled.
"I"m sorry," Doc said.
The bronze man then backed out, and went back to his men.
"They have a guard," he said.
Long Tom growled, "I"ll get a messenger boy"s uniform. I"ll take him a telegram-and bop him on the head."
"It will not work," Doc said.
"No?"
"The guard is holding a push b.u.t.ton in his fist," Doc explained. "The moment he releases it, an alarm will probably start ringing."
"Holy cow!" Renny rumbled. "Then we can"t gas the guy, or rush him, or nothin"!"
That was about the situation.
Doc Savage said, "Wait here."
"But-"
"The fireworks will start in about twenty minutes," Doc said. "When it does, you fellows use your own judgment."
DOC SAVAGE got in the coupe, took the express highway south, making as much speed as possible without menacing other traffic. Later he pulled up before his water-front warehouse-hangar.The hangar portion of the building housed a number of planes, ranging from a huge speed ship-three-motored, capable of making a jump half around the world on one fueling-down to a small gyro, or "windmill", which could descend vertically.
Doc took the gyro. He ran fuel into the craft, started the motor, and while it was warming, opened the great doors in the river end of the hangar. The plane was equipped with both pontoons and retractable wheels, so it could operate from land or water.
The bronze man loaded equipment he needed for the immediate project. He guided the craft out on the river, and took to the air.
It was late afternoon. Sidewalks of Manhattan spread below, crowds hurrying from work. Down the bay, two liners were leaving, one behind the other, headed out to the Atlantic Ocean. The sea stretched away in gray-blue flatness until it was lost in the haze. Few clouds. The clouds were very white.
Doc flew north, the gyro nose pointed upstairs, gaining alt.i.tude. When he was high over the lower end of Riverside Drive, he cut the motor. The craft began to settle. The windmill craft did not glide forward after the fashion of an ordinary plane, but settled straight downward.
From time to time, Doc gave the craft enough headway for maneuverability, so he could keep descending directly above the roof of the tall apartment hotel on Riverside Drive.
The sole sounds the gyro made were about the sounds that a big bird would make flying.
Doc hung his jaw over the c.o.c.kpit edge, watched. He studied the penthouse, judged possibilities. It did not look so good.
This building, unlike many structures on Manhattan, did not have a water tank tower on the roof. The roof was flat and un.o.bstructed, except for some wires which appeared to be a radio aerial. So far, good.
But the penthouse itself was a wide building of Spanish architecture, with a sloping tile roof and a patio in the center. In the patio there was a swimming pool.
All the rooftop surrounding the penthouse had been planted in gra.s.s and shrubbery. That was the bad part. It would be like landing in a backyard rock garden.
There was no doubt that the plane could get down safely. Whether it could take off again was doubtful.
Two hundred feet over the roof, Doc dropped two large grenades overside. They were not explosive grenades. These contained anaesthetic gas. Being fish-shaped and stream-lined, the grenades fell faster than the craft, and hit the roof ahead of it.
Doc had time to put on an abbreviated gas mask.
First, the gyro hit a radio aerial. It tilted. It slid sideways, landed with a crash. Undercarriage snapped, the ship tipped over, two of the rotor blades smashed into the shrubbery and lost shape.
Doc was out of the craft instantly; he seemed to bounce out. He went headlong for shelter of bushes. The shrubs grew in sunken boxes of earth.
Doc made concealment, waited and listened.
SCREEN doors banged and men came tearing out of the penthouse to see what had happened."A plane hit the roof!"
"h.e.l.l"s bells!"
A strangled sound; the noise of a body falling. At least one man had inhaled the gas.
"Hey! What"s happened to Joe?"
"It"s gas!"
The screen doors all banged again as the men ran back inside. Next, there was shouting in the penthouse.
Rushing around. Excited bawling of orders.
Someone began to pump bullets through a window into the plane. The gunman fired methodically, emptying clip after clip, five shots to the clip, into the craft.
A louder voice now shouted angrily that they would have to leave, that the uproar would bring the police.
"Get the prisoners into the elevator!" this voice ordered.
Doc Savage worked through the shrubbery to a window. He tried it. The sash was open. He shoved it up, dived through into a room which had a bare tile floor and furniture of Spanish type and a gaudy blanket hanging on one wall.
Doc whipped across this room to a door, had almost reached it, when a man came through holding a gun. The gun holder asked no questions. He fired.
Doc Savage, twisting, bent down to let the bullet pa.s.s over his head. There was a rug on the floor; Doc yanked it. The other man tilted over, firing again, his bullet gouging plaster out of the ceiling.
Doc got hold of the gun arm, and the arm went out of joint and the man began screaming, one shriek after another, in agony.
There was now shouting through the penthouse, enough to indicate men were running to see what had happened. Doc tossed a smoke bomb through the door. It was a small bomb, but it made big smoke. A pall of sepia spouted, grew; smoke that was as black to the eye as drawing ink from a bottle. The charging men got in the smoke and swore and shot off guns.
DOC SAVAGE left the room through the window by which he had entered. Looking for another way in, he came to a window covered with steel shutters.
The window shutters were shaking; someone was pounding on them from the inside. The one doing the pounding was also yelling in a squeaky voice that could be recognized anywhere.
Monk! It was Monk!
A bar fastened the shutters from the outside. Doc wrenched the bar loose, got the shutters open.
Monk peered at Doc. "Who-who the blazes are you!"
"Isn"t it Doc Savage?" Miami Davis demanded.
"It don"t look like him!" Ham said.Which was a tribute to the bronze man"s disguise as an old man.
"Out!" Doc said.
He could talk through his gas mask.
The girl came through the window, then Ham. Monk, coming last, all but got wedged.
Ham peered at Doc"s size.
"It"s Doc all right," he said. "But-but they told us they blew up-"
"How do we get out of here?" Doc demanded.
Ham said, "There"s only one way out; that"s the elevator."
Inside the room the prisoners had just vacated, there were yells. The escape was discovered.
"Away from here!" Doc said.