I thanked him, and, passing through the opening, entered a kind of paved yard, on three sides of which were quaint narrow little houses with old-fashioned window-panes. The second doorway bore a carefully polished brass plate, with the inscription "James Campbell. Private Enquiry Agent."

I was just hunting around for a bell when suddenly the door swung back, and, looking up, I found myself face to face with the Inspector himself. He was evidently on the point of going out, for he was wearing a bowler hat and carrying a walking-stick.

Directly he saw me his big square-jawed face lit up in a smile of welcome.

"Why, it's Mr. Dryden," he exclaimed, holding out his hand. "Well, this is a bit of luck. If you had been a moment later you'd just have missed me."

"It's my lucky day," I said "But, all the same, I mustn't keep you if you've got an appointment."

"It's nothing very important," he replied. "Come along inside. I can spare a minute or two anyhow."

He led the way into a comfortably furnished office on the right, and, pulling forward a chair, seated himself exactly opposite me. His large and very wide-awake blue eyes scanned me with friendly interest.

"I'd better start by apologising," he began. "You mustn't think I've forgotten your invitation to come down and have a bit of shooting, but the fact is I've been so busy I've had no time to write. People have been misbehaving themselves the last three weeks in a way you wouldn't believe; I suppose it's the hot weather."

"I shouldn't wonder," I said. "I've felt a little vicious myself once or twice." I tossed away the stump of the cigar I was holding and helped myself to another from the case which he offered me. "As far as the invitation goes," I added, "it's open permanently. I am not the sort of a person who wants a lot of notice. Just send along a wire as soon as the crime wave subsides."

"The very minute," he said with a twinkle. Then, putting his thumbs in his waistcoat, he leaned back comfortably in his chair. "And how are you getting on down there?" he asked. "You know, I take a special interest in your affairs, Mr. Dryden. There's something about Greensea Island that I didn't quite get to the bottom of, and no one likes to be hit in his professional pride."