Patsy Garvan arrived at the Osgood Hospital soon after six o’clock that evening, more than two hours before Chick encountered the masked man in Gaston Todd’s apartments.

It then was dark, the sky clouded, with no stars to reveal his stealthy movements to chance observers. Only the scattered street lamps and the numerous lighted windows of the great building, with those of a few more distant dwellings, relieved the prevailing gloom. It was even darker in the deserted grounds, and Patsy took advantage of the trees and shrubbery, entering the extensive estate near one corner, and stealing quickly around the west wing toward a rear part of the main building in which the private room of Doctor David Devoll was located.

Patsy knew from Carter’s description, nevertheless, where to find him, and he presently paused near the rear door and the gravel walk leading out to the back street.

“I must find out, to begin with, whether the blooming sawbones is here,” he said to himself. “There are the two windows of his room, all right, but there’s no sign of a light. It looks very much as if he were absent.”

Hugging the wall, and stealing closer, nevertheless, he cautiously crouched under the nearer of the two windows and tried to peer into the room. He then found that the roller shade was lowered and an interior shutter carefully closed, but through a chink below them he could see the reflection of a dim light on the varnished sill.

“Gee whiz! he makes dead sure that no outsider can see what’s doing in there,” thought Patsy. “He may be in some other part of the hospital, since only a dim light is burning. I’ll have to stick round till I can get an eye on him.”

As a matter of fact, however, Patsy had arrived there in the nick of time. The light in the room was suddenly extinguished. Half a minute later the sound of a turning knob, that of the rear door, broke the outside stillness, and, as quick as a flash, Patsy dropped flat on the ground close to the building.

He scarce had taken this precaution when the door was opened and the physician came out. Though Patsy never had seen him, Nick Carter had described him carefully and there was no mistaking him. His slender figure, invariably clad in a black frock coat, which accentuated his leanness, was one very easily identified. His smooth-shaven face was dimly discernible through the darkness, while a considerable portion of his bald, white skull could be seen in vivid contrast under his tall, black hat.

“Gee! I’m playing lucky, after all,” thought Patsy, cautiously watching him. “That’s my man, all right, and he’s bound off. The chief was right in thinking he would make a move of some kind.”

Doctor Devoll had paused to lock the door with a key taken from his pocket. He did not so much as glance toward the window under which Patsy was lying, as flat as he could make himself on the damp greensward. With his head and shoulders thrust forward and his hands clasped behind him, an habitual attitude when he was walking, Doctor Devoll proceeded down the gravel walk toward the rear gate.

At that moment, too, Patsy caught sight of an approaching motor car in the back street. Its lamps shone through the trees, and he could see that it was slowing down to stop at the gate.

“By Jove! I may not be as lucky as I thought,” he muttered apprehensively. “If he leaves in that car it will be a racking stunt for me to keep track of it. I’ll make a bid to do so, all the same.”

Rising noiselessly, he now darted after the physician, stealing from tree to tree, and seeking a point from which he could get the license number of the car, and also a look at its driver. He saw him quite plainly a moment later, a powerful man wearing a slouch hat and with the collar of his overcoat turned up, partly hiding his face, a face that immediately increased Patsy’s suspicion.

Doctor Devoll paused and said a few words to him; then entered the car and disappeared, for its leather curtains were on and completely hid the interior. Then the chauffeur threw in the clutch and the car moved away.

Patsy Garvan appreciated the difficulties confronting him, but he did not let them daunt him. Running diagonally across the gloomy grounds, he vaulted the low iron fence immediately after the car had passed that point, so near that he could easily read the rear number plate. He fixed the number in his mind; then darted stealthily after the car, which was entering the narrow court through which Chick had passed that morning.

Sprinting after it at top speed, though at a discreet distance behind and in the deeper gloom near the buildings, Patsy followed the car into Belmont Street and saw that it had turned toward a more brightly lighted business section in the distance. He could see a passing trolley car, also several slowly moving wagons, all of which was somewhat encouraging.

“They’ll have to slow down in that quarter,” he muttered, already breathing hard from his exertions. “That must be Main Street. It’s just the time when the business thoroughfares are blocked with homeward-bound teams. I may be able, after all, to keep my quarry in sight. I must contrive in some way to find out where this baldheaded suspect is going.”

It appeared like a hopeless pursuit, nevertheless, for the motor car was speeding much more rapidly through Belmont Street and leaving Patsy farther and farther behind, in spite of his utmost exertions. Suddenly, too, it turned down a street running parallel with Main Street, evidently seeking a less-congested way.

Patsy rushed on all the while, hoping to arrive at the corner in time to keep the car in view, but he was booked for failure. He paused, panting for breath, and gazed vainly up and down the street. The only vehicle to be seen was an approaching wagon nearly a block away. Sprinting on to meet it, determined not to be thwarted, Patsy shouted to the driver:

“Did a motor car pass you half a minute ago?”

“Yes,” cried the teamster. “Some one stolen it?”

“Yes.” Patsy took the quickest and surest way to get the information he wanted. “Which way did it go?”

“Through the next street to the right, toward Main Street. You’ll have to fly, kid, to catch it.”

Patsy rushed on again, scarce waiting for the last, but again he was marked for failure. He arrived at the corner too late to see the car. Only the moving people and vehicles in the electric glare in Main Street, then only a block away, met his anxious gaze.

“I’ll keep on, by thunder!” he muttered, instantly resuming the pursuit. “It may have been held up for a moment. It must have turned to the left, too, or it would have gone direct if intending to cross Main Street. I’ll not quit, by gracious! while there’s a ghost of a chance to overtake it.”

Patsy’s grit was good, but his quest proved vain again, and he had no alternative but to end the futile pursuit. He gazed with bitter disappointment up and down the broad thoroughfare, still walking briskly in the direction in which he knew the motor car had gone, and, though he was not then aware of it, he presently came to a crosstown street and trolley line within a stone’s throw of the Waldmere Chambers.

Then, as he was about to return to the hotel to report to his chief, the gloom of disappointment was suddenly dispelled. The motor car was passing rapidly through the crosstown street. There was no mistaking it—the same number plate, the same muffled driver, the same closely curtained tonneau, yet in which Patsy caught a mere momentary glimpse of a solitary figure.

“Holy smoke! I’m in luck again,” he said to himself, with a thrill of elation. “The doctor must have stopped somewhere and now is off in a new direction. This looks like soft walking, for fair, if they will only follow the trolley line.”

An electric car going in the same direction was passing, and Patsy quickly boarded it, joining the motorman on the front platform. Slipping him a bank note, he said confidentially:

“Don’t ask any questions, but help me to keep that motor car in sight. Do you get me?”

The motorman glanced at him with a look of surprise; then thrust the bank note into his pocket and grinned.

“Sure I get you,” he replied. “No questions, eh? That’s good enough for me, though they do say money talks. I’ll do the best I can for you.”

The automobile then was fifty yards in advance, but the trolley car was unobstructed and rapidly gaining speed through a street running straight toward an outskirt of the city.

“Good for you,” replied Patsy. “Only a mutt would expect more.”

“I’ll keep it in sight, all right, unless I get the bell too often. But we’re not carrying many this trip.”

“Where do you run?”

“To Ashville, six miles from here. But we hit the suburbs soon; then can cut loose, if necessary. Do you know where the buzz wagon is going?”

“If I did, I would not bother you,” smiled Patsy. “I have reasons for wanting to find out, if possible. Did you see the driver when he slipped in ahead of you?”

“I didn’t notice him.”

“You don’t know who owns the car, then?”

“I don’t, but you can find out from the number.”

“I’ve got that in my head, all right,” Patsy nodded. “I’ll look him up later.”

The motorman glanced at him again, and wondered at his interest in a car and persons whom he did not know or even their destination. He kept the trolley car moving rapidly, nevertheless, and, in spite of an occasional stop to drop or pick up passengers, he lost but little on the somber black touring car, the tail light of which gleamed like a sanguinary eye through the gloom in the near distance.

A mile run took them into the suburbs, beyond which was a stretch of almost open country, and Patsy then had the satisfaction of seeing that the trolley car was gaining on the other.

Through this open country and into a belt of woods the trolley car boomed on, and when nearly three miles out it sped over the brow of a hill, and Patsy quickly saw the lights of scattered dwellings amid clumps of trees in the distance.

“What place is that?” he inquired of the motorman.

“Only a small settlement. There’s a stone quarry over the hill on the left, and the workmen live in those houses. That one off to the right is in a side road running to Lakeville, where there’s pretty good fishing and gunning in the season. It’s a road house run by a man named Leary. I guess that’s where your buzz wagon is going. It’s taking that road.”

Patsy had an eye on it all the while, and saw that the time had come for him to leave the trolley car. He thanked the motorman again; then added:

“Slow down when near that road and let me drop off without stopping. I don’t want a certain party to hear the car stop. He might think he had been followed.”

“I’m on,” said the motorman, laughing. “You know your business, all right.”

“I ought to,” smiled Patsy. “I was tutored by the best in the business.”

“I guess not,” said the motorman incredulously. “There’s only one best—Nick Carter.”

“So I have heard.”

“Now’s your chance. So long, and good luck.”

Patsy slipped through the folding door and sprang down in the road, then darted to the shelter of a wall, while the trolley car again sped on and presently crossed the diverging road and approached the settlement beyond it.

A hundred yards to the right the lights of the road house could be seen through the trees, also the brighter glare from the motor car, then slowly approaching it.

Patsy leaped over the wall; then hurried across a strip of meadowland, quickly reaching a point from which, sheltered by some shrubbery, he could plainly see the broad driveway and front veranda of the old and somewhat weather-beaten house.

The automobile had stopped near the rise of steps. The chauffeur was springing down to open the door. Patsy could see him distinctly in the light from the deserted veranda.

“This bald-headed doctor may have legitimate business out here,” he muttered, frowning grimly at the mere thought of it and the possibility that his own desperate efforts might prove futile. “If the chief’s suspicions have feet to stand on, however, it’s a thousand to one that Doctor Devoll’s mission is a very different and probably a very lawless one. It’s up to me to clinch it and find out just what’s doing. If he’s here to confer with others, or frame up a job, I’ll find some way to overhear him——Thundering guns! Am I in wrong, in dead wrong, after all?”

Patsy felt a chill of disappointment and his heart sank like lead. The door of the motor car had been opened. The solitary occupant, and Patsy could plainly see there was no other, was stepping down upon the driveway. He was an elderly man with gray hair and beard, with a compact, apparently muscular figure, clad in a plaid woolen suit and soft felt hat—utterly unlike the long frock coat and tall black hat of the suspected physician.

“In wrong, in dead wrong!” Patsy repeated, quite crushed with sudden dismay. “That’s not my quarry—not Doctor Devoll. He’s too straight, too erect, too square and stocky, for Doctor Devoll. I’ve gone lame, for fair, as lame as an army mule. That chauffeur must have dropped the physician and picked up another passenger.”