To all intents and purposes, Minter was staring into an ordinary hollow tree. The rock plug which The Shadow had replaced hid effectively any sign of the secret tunnel that connected the tree with a spot across the lane beyond the stone wall.

Minter's face was pale in the ray of his torch.

"It lacks only two minutes of eleven," he whiskered. "Shall I put the money inside the tree?"

"By all means," Swade said.

Kilby handed the satchel to Minter. The banker himself dropped the blackmail money out of sight. It landed with a rea.s.suring thud. The eyes of Swade and Kilby gleamed.

"Now to unlock the entrance gate to the grounds, as the blackmailer directed," Kilby said in a low voice.

"We've got to make him think his instructions are being carried out to the letter. It is the only sure way to nab him."

Again they left the job to Minter. He unlocked the heavy metal gate, swung it ajar. It left plenty of room for a furtive visitor to sneak through and approach the baited tree. There was sweat on Minter's pale forehead.

"How shall we work it, gentlemen?"

Swade did the explaining. He seemed calm and resolute. Minter took comfort from his voice, and fromthe rea.s.suring pat of Kilby's hand on his shoulder.

"Here's the idea," Swade said. "I'll explain each of our jobs in turn. Mine first. There's a tree that grows close to the stone wall a few yards from here. A branch of that tree bends outward over the top of the wall. I shall climb that tree in a moment and wait there out of sight It will give me an easy opportunity to scale the wall, if necessary, and drop to the lane outside. You understand?"

"Yes," Minter whispered.

"Now, for your job and Kilby's. It will be better if both of you keep in sight of this hollow tree. The best stunt will be for each of you to hide in a clump of bushes close to the opened entrance gate. In that way, you can keep a sharp eye on the gate and on the hollow tree. It will then be impossible for anyone to sneak through the gate and approach the tree without detection. Is that clear?"

They nodded.

"If each of you pick a covert," Swade went on, "where you can see each other, you will be able to exchange a quiet signal the moment either of you spots the approach of the blackmailer."

"Right," Kilby said.

Swade laughed briefly.

"Now, for the actual nabbing of the crook. If the blackmailer sneaks through the open gate and grabs the money satchel from the hollow tree - he's our man! You two can cut off his escape from the grounds.

Minter darts to the entrance gate, slams and locks it. Kilby tackles the thug; shoots him, if necessary."

"Suppose the criminal is too fast?" Minter whispered. "Suppose he gets out the gateway before I have a chance to lock it and pen him inside the wall?"

"That's where I come in," Swade chuckled. "If he reaches the lane, I'll be there to cut him off. At the first roar of Kilby's gun, I shall drop from my tree branch to the road. Instead of escaping with the cash, our unknown foe will stay on that lane - with a couple of my bullets in his body to make sure he doesn't get away! How does it sound, gentlemen?"

"Excellent!" Kilby murmured. "Our man is as good as caught."

"Then let's waste no more time," Swade rasped.

There was a faint smile on his lips as he glanced at Kilby. Kilby was grinning slightly, too.

Swade vanished into the darkness. Kilby faded into a covert. Jonah Minter vanished into another.

FROM where they stood, each could see the other. Or so the deluded Jonah Minter thought. Actually, he saw the dark blur of Kilby's body for only a few moments. Kilby had no intention of remaining in that covert.

He slid quickly out of his coat. He propped the coat cleverly so that a sleeve was visible to Minter, and part of what looked like a hunched shoulder. The brim of Kilby's hat, perched above the empty coat, completed the illusion of a motionless figure in the dark shrubbery.

The foxy Kilby did one thing more. It would have brought a gleam of grim understanding to the eyes of The Shadow, had he been able to see what was going on.

From a matted hummock of gra.s.s in the center of the leafy covert, Kilby produced a dark bundle. Swiftlyhe donned something, placed another hat on his bared head.

He had donned the cloak and the slouch hat of The Shadow!

It was the regalia that had disappeared so strangely from the projection booth of a movie theater a few days earlier.

Kilby had no intention of sharing the blackmail loot with Swade on a fifty-fifty basis. He was after all, or nothing! Jonah Minter wasn't the only dupe to be tricked tonight.

Garbed as The Shadow, Kilby sneaked noiselessly from the thicket where Minter was positive he still remained. He crept along the underbrush on the inner side of the estate's wall. He took a direction opposite to that taken by the sly Simon Swade.

Presently, Kilby found the spot he wanted. It was easy to gain the top of the dark stone wall. Kilby rose invisibly through the blackness.

THE SHADOW was unaware of this sinister development.

Hidden near the entrance to the earth tunnel on the opposite side of the lane, The Shadow waited. His back was toward the direction in which the cunning Kilby had faded. His gaze remained on a different part of the estate wall.

Over that spot was the projecting branch of a tree. A figure was on that branch - a figure that crept noiselessly outward. Presently, The Shadow saw the man's feet touch the wall top. An instant later, the wall was bare.

Swade had lowered himself silently to the lane!

The Shadow knew it was Swade in a few seconds. He saw the figure cross the lane swiftly, step with careful haste into the tangle of woodland where the entrance to the tunnel was located.

Swade's face wore a bleak grin as he bent over the cunningly concealed hole in the ground. The Shadow had left no trace of his own journey through that earth pa.s.sage a short while earlier. Swade was unsuspicious of danger.

He crawled down the slanting entrance to the tunnel that led to the hollow tree where the blackmail money waited in a leather satchel.

The Shadow remained invisible. He did not interfere. The time to nail Swade would come when he emerged from the hidden tunnel with the loot.

Blackness of the night seemed to be charged with a foreboding hush as The Shadow waited. Then a loose pebble rattled faintly.

Swade was emerging from the tunnel with the loot. The Shadow saw his head rise from the hole. He was carrying the leather satchel. He began to move noiselessly from the tunnel mouth to another spot.

The Shadow began to move, too. He was eager to see where Swade intended to cache the loot.

He soon discovered. Swade bent close to the tangled ground. He was in a covert about fifty feet away from the hidden tunnel entrance. He lifted a bed of ferns as if their thick green growth were a solid trapdoor.

It was! Beneath the ma.s.sed ferns was a square section of wood that covered a shallow hole. Into thishole went the leather satchel.

Simon Swade started to rise. Then his eyes bulged with surprise - and terror. As he rose to his feet, he found himself facing The Shadow!

The startled Swade had no chance to yell. A blow from his black-robed foe knocked him, dazed, to the ground. The leather satchel was s.n.a.t.c.hed from its spot of concealment. The Shadow fled!

The Shadow's flight was watched grimly by - The Shadow!

A triple cross was complete! With the highjacked loot in his greedy grasp, the fake Shadow vanished along the dark lane toward the estate wall.

And still the real Shadow waited!

CHAPTER XI. TRIPLE CROSS.

THE SHADOW'S delay was deliberate. He divined the ident.i.ty of that black-robed counterfeit of himself. The highjacker couldn't be Swade. Or the duped Jonah Minter.

It could only be Dr. Anthony Kilby!

Knowing this, The Shadow allowed the disguised thief to mount the stone wall of the estate and drop silently back to the dark grounds.

An instant later The Shadow himself scaled the wall at a different spot. He crept closer to the unsuspecting fugitive in the black cloak.

The Shadow wanted to know the final hiding place of the loot. He knew that Kilby would have to ditch it in order to keep his triple cross a secret. The Shadow was anxious to keep tabs on the climax of this cunning piece of criminal deception.

Invisible and silent, he watched Kilby melt into a thicket. The stolen cloak and the slouch hat were quickly doffed. They were hidden inside the thicket. So was the leather satchel that contained fifty thousand dollars.

Kilby didn't waste a motion. He was eager to return to the covert close to where he had left the gullible Jonah Minter. He had to be there before the slugged Swade recovered his addled wits and raced back to the hollow tree rendezvous.

Kilby reached his goal without making a betraying sound. He replaced on his head the hat he had propped up to fool Minter. Sliding into his empty coat, he deliberately stuck his head well into view from the dense thicket. The Shadow heard him call out in a cautious whisper.

"Minter! Are you still watching the gate?"

"Yes! No one has come into the grounds yet. Do you think the blackmailer got frightened and skipped without trying for the money?"

"I don't know," Kilby whispered. "It looks queer."

To The Shadow, it was far from queer. Inaudible laughter twitched the muscles of his throat. He had seen enough to realize the cunning nature of Kilby's alibi. He melted backward into the darkness.

The Shadow retreated in the direction of the spot where the money satchel had been left by a shrewdthief.

Unaware that his scheme had been detected by The Shadow, Kilby now left his place of concealment.

He was joined in the open by Minter.

"No one came near that tree," Minter whispered. "I'll swear to it!"

"Nor through the driveway gate," Kilby said. "We've both had an eye on it ever since Swade left. I wonder if he's seen anything."

Minter didn't answer. With a tremulous hand, he sent the exploring beam of his; flash into the hollow interior of the chalk-marked tree. His cry was shrill with amazement and alarm.

"It's gone!"

"Gone? You mean the money is no longer - That's impossible!"

Kilby seized the flashlight from Minter's nerveless grasp. He seemed stupefied to discover that the hollow tree was now empty.

Suddenly there was a crashing sound in the bushes. Kilby turned, leveled his gun. He lowered the weapon with a gasp of fake relief when he saw who the new arrival was.

It was Swade.

Swade didn't say anything for a moment. He suspected that Kilby had been his black-robed a.s.sailant. He had hoped to rejoin Minter before Kilby returned. He realized now that he had been too slow; so he decided to play dumb.

"Looks as if our plans went wrong," he growled. "The blackmailer must have gotten cold feet. He never showed up."

"Oh, but he did!" Minter shrilled. "The money is gone!"

"Then why didn't you lock the entrance gate? Why did you let him get away? Why didn't you signal me?"

"There was no one to see," Kilby said. "It sounds completely crazy! Surely, the criminal wasn't invisible!"

He turned away for an instant, his back to Minter. He used the swift maneuver to whisper at Swade's ear: "You worked it beautifully! Did you hide it safely?"

Swade had to grind his teeth to conceal his rage at the smooth hypocrisy of his partner. But he smothered his feelings.

"I didn't get it," he replied in a whisper. "Something went wrong."

MINTER was still babbling incoherently in the darkness. He was too stunned to think of looking for a logical explanation of how a satchel filled with money could have left a tree unseen. The thought of a tunnel had not yet occurred to him.

Swade didn't allow it to. He grabbed Minter by the arm, said: "Are you sure that you and Kilby were in plain sight of that hollow tree - and of each other - all the time Iwas away?"

He waited for the answer that would expose his cunning partner. But he got a reply that he didn't expect.

"Of course," Minter cried. "Kilby and I were visible to each other the whole time you were away!"

His voice carried conviction. Kilby, too, underwent the scrutiny of Swade with complete composure.

Swade was baffled. His ugly suspicion of Kilby began to fade. He wondered uneasily if the black-robed foe who had slugged him and escaped with the loot might not be - The Shadow himself!

Sweat broke out on his forehead. He turned aside from Minter. His sly lips grazed the ear of Kilby.

"I was highjacked! The Shadow swiped the satchel!"

"The Shadow!"

Kilby put fake consternation into that breathless whisper. Then he added a more ominous remark: "Is this a gag? Are you trying to gyp me out of my half share?"

"It's true! The Shadow slugged me after I came out of the tunnel. He grabbed the satchel and faded. I don't know where!"

"Good lord! Maybe The Shadow is right here in the grounds!"

Their whispers ceased as Minter turned in their direction. He was beside himself with rage. Minter had suffered a double disaster. His money was gone; the blackmailer was still uncaught.