Spurred by the courtesy and confidence of his superior, Rob devoted himself with energy to the work of unravelling the mystery, but it was baffling work. As he confessed to Kitty French, who was in all things his confidante, every avenue of argument led up against a blank wall.

“Either Carleton did do or he did not,” he said reflectively. “If he did, there’s absolutely no way we can prove it; and if he didn’t, who did?”

Kitty agreed that this was a baffling situation.

“What about that cachou, or whatever you call it?” she said.