CHAPTER I

"Night, Mason!" Detective-Sergeant Grime, walking through the main hall at Police Headquarters, Hunter-street, Sydney, halted beside Inspector Robert Mason. "Working back?"

"Waiting for Anderson," Mason answered, pacing towards the main doors with the sergeant. "What a night! You'll have trouble in getting to North Sydney through this fog. Better telephone home and stay over here. I can put you up."

"Thanks, no. The missus is always nervous nights like these, alone in the house. I'll have a shot for the ferry. If I can't get across I'll come back and knock you up."

"Do." Mason peered out on the dark streets up which the fog was rolling in long, white billows. "About the worst fog Sydney's ever had."

"Bur-r-r!" Grime turned up the big collar of his overcoat and snuggled his hands into the pockets. "Glad I'm not on duty. Just the night for the Shadow Crook!"

"The Shadow Crook?" Mason laughed. "Is there such a person?"

"You wouldn't ask that question if you were up in Darlinghurst." Grime shrugged his shoulders. "They're convinced the Shadow Crook's real believe me. Well. I'll get along. See you to-morrow, if nothing happens."

The sergeant ran down the half-dozen steps to the pavement and went to cross to The Hunter-Phillip streets corner. He had barely stepped from the pavement when a thick billow of fog rolled up Phillip-street, and blotted him from the Inspector's sight.

Mason stood on the steps for some seconds, peering out on the ill-lit streets. With an involuntary shudder he turned to re-enter the building. Then he noticed a man leaning against one of the stone pillars of the entrance. At the moment, the man looked up and their eyes met. The man turned away, immediately, and his sparse, ill-covered frame was shaken with violent spasms of coughing.

"Better get under cover, my friend, with that cough." Mason spoke kindly. "This is not the sort of night for you to be out in. Here, wait a minute."

He strode: in to the hall, and to the Inquiry Desk. In a few seconds he returned to the street, carrying a glass of water. The man had disappeared. For a time the Inspector stood on the pavement searching the street so far as he could see in the fog. Then, with an impatient exclamation, he poured the water in the gutter and returned the glass to the desk.

"Wonder where Sergeant Anderson's got to?" he remarked to the constable on duty. "I've been waiting for him a full quarter of an hour."

"Came down the stairs a few minutes ago, Inspector, and went toward his room," the man replied. "Seemed in a bit of a hurry."

"Did he?" Mason turned toward the corridor on the right of the hall. "I'll hurry him for those records he promised to let me have to-night."

At the third door on the left-hand side of the corridor Mason stopped and tried the handle. The door was locked. He listened but could hear no movement within the room. As he stepped hack he noticed under the door a thin line of light. Anderson must have left a light burning in his office. That meant he would return in a very short time. Thrusting his pockets, Mason strolled towards the main hall.

"Not there!" The Inspector leaned against the counter. "Anderson seems to be doing a lot of travelling to-night. Wish he'd hurry up. This isn't a night to be standing about waiting-"

The lights in the hall suddenly failed. The Inspector felt in his pocket for a match. By the faint light he saw the constable in a corner fumbling at the switches. He stepped cautiously through the hall. Not a light was to be seen anywhere. He went to the foot of the stairs and looked up. The upper floor was in darkness and from the distance came sounds as of bees disturbed in their hive. With a slight laugh he turned back to the Inquiry Desk, guided by the matches the constable was striking.

"Total eclipse, Clarke," he said lightly. "Thick darkness all over the building.