“Now what about this blue-print?” he queried sharply.

Dale stiffened in her chair.  Her lies had failed.  Now she would tell a portion of the truth, as much of it as she could without menacing Jack.

“I’ll tell you just what happened,” she began.  “I sent for Richard Fleming—­and when he came, I asked him if he knew where there were any blue-prints of the house.”

The detective pounced eagerly upon her admission.

“Why did you want blue-prints?” he thundered.

“Because,” Dale took a long breath, “I believe old Mr. Fleming took the money himself from the Union Bank and hid it here.”

“Where did you get that idea?”

Dale’s jaw set.  “I won’t tell you.”

“What had the blue-prints to do with it?”

She could think of no plausible explanation but the true one.

“Because I’d heard there was a Hidden Room in this house.”

The detective leaned forward intently.  “Did you locate that room?”

Dale hesitated.  “No.”

“Then why did you burn the blue-prints?”

Dale’s nerve was crumbling—­breaking—­under the repeated, monotonous impact of his questions.

“He burned them!” she cried wildly.  “I don’t know why!”

The detective paused an instant, then returned to a previous query.

“Then you didn’t locate this Hidden Room?”

Dale’s lips formed a pale “No.”

“Did he?” went on Anderson inexorably.

Dale stared at him, dully—­the breaking point had come.  Another question—­another—­and she would no longer be able to control herself.  She would sob out the truth hysterically—­that Brooks, the gardener, was Jack Bailey, the missing cashier—­that the scrap of blue-print hidden in the bosom of her dress might unravel the secret of the Hidden Room—­that—­

But just as she felt herself, sucked of strength, beginning to slide toward a black, tingling pit of merciful oblivion, Miss Cornelia provided a diversion.

“What’s that?” she said in a startled voice.

The detective turned away from his quarry for an instant.

“What’s what?”

“I heard something,” averred Miss Cornelia, staring toward the French windows.

All eyes followed the direction of her stare.  There was an instant of silence.

Then, suddenly, traveling swiftly from right to left across the shades of the French windows, there appeared a glowing circle of brilliant white light.  Inside the circle was a black, distorted shadow—­a shadow like the shadow of a gigantic black Bat!  It was there—­then a second later, it was gone!

“Oh, my God!” wailed Lizzie from her corner.  “It’s the Bat—­that’s his sign!”

Jack Bailey made a dash for the terrace door.  But Miss Cornelia halted him peremptorily.

“Wait, Brooks!” She turned to the detective.  “Mr. Anderson, you are familiar with the sign of the Bat.  Did that look like it?”