Down they swept until Ronnie, an expert in landing at night, found himself in a large grass-field. Collins came running forward eagerly to welcome him.

The four lights were at once extinguished, and the engine being shut off, all was quiet again.

“Well, sir, I think you’re quite right,” Collins said at last. “I’ve been watching these two days, and there’s something mysterious in the wind.”

“Have you seen them?” asked Ronnie eagerly.

“Yes. A youngish man and a stout old woman. When I got down I found Shawfield to be only a tiny place with one old inn, The Bell, and I knew that a stranger’s movements would be well watched. So I went three miles farther, and took a room at The George, in Bricklehurst.”

“How far is the farm from here?” asked Beryl.

“Oh, about a mile—not more, miss! Behind that wood yonder,” he replied. “They had a visitor this afternoon—a tall, fair, well-dressed man. He’s probably spending the night there. I watched him arrive at Shawfield Station, and the man who calls himself Cator met him, and drove him in the car to the Manor Farm.”

“I wonder who the visitor is?” remarked Pryor.

“He is probably one of the gang,” Beryl suggested. “No doubt he has come down from London to see them in secret. The woman poses as Cator’s mother, I believe.”

“Yes, miss. I’ve discovered that they bought the Manor Farm in 1913, and that Cator had an excellent assistant, a Belgian, it was supposed—or at least he gave himself out to be that. Cator erected new farm-buildings that you will see—nice, red-brick structures with corrugated iron roofs, and spent a large sum of money on improvements.”