“Yes, and we know a great deal to start on.” Wise spoke thoughtfully. “We know, almost to a certainty, that it is the man whom we call Stephen, because he wrote threatening letters signed ‘Step.’ We know he is diabolically clever, absolutely fearless, and willing to commit any crime or series of crimes to gain his end, which is merely the large sum of money he has demanded from Mrs Varian, and which he had previously demanded from Mr Varian, as blackmail.”

“Why should he blackmail my husband?” Minna asked, tearfully, and Wise said, “There is not always a sound reason for blackmail, Mrs Varian. Sometimes it is an unjust accusation or a mistaken suspicion. Any way, as you have often declared, Mr Frederick Varian was a noble and upright man, and his integrity could not be questioned.”

“Now, then,” said Doctor Varian, “to find this master hand at crime. I am astounded at your revelations, Mr Wise, and I confess myself utterly in the dark as to our next step.”

“An animal that attacks in the open,” Wise returned, “may be shot or snared. But a wicked, crafty animal may only be caught by a trap. I propose to set a trap to catch our foe. It is a wicked trap, but he is a wicked man. It will harm him physically, but he deserves to be harmed physically. It is a sly, underhand method, but so are his own. Therefore, I conclude that a trap is justified in his case.”

“You mean a real, literal mantrap?” asked the doctor.

“I mean just that. I have already procured it and I propose to set it tonight. This is Thursday. As matters stand now, our ‘Stephen’ is assuming or at least hoping that Mrs Varian means to accede to his last request and throw the money over the cliff tomorrow, Friday night. Now, I feel pretty positive that Stephen is not so confident of getting that money safely as he pretends he is. He must be more or less fearful of detection. I’m sure that he will return to this house tonight, by his usual mode of entrance, and will try to steal the money. Then he will disappear and he may or may not give up Betty.”

“You think he’ll come here? Tonight?” Doctor Varian was astonished.

“I do.”

“Then we’ll be ready for him! I fancy between us, Mr Wise, we can account for him and his accomplice.”

“Too dangerous, Doctor. He would kill us both before we knew it. No, I’m going to set my trap. If he comes he deserves to be trapped. If he doesn’t come, there is certainly no harm done.”