"What do you want me to do?" asked Forrester.
"Well, you see it's this way," explained Cahill. "If those Dagos come back to the garage between now and Saturday, we'll have them. But if they get wise that we found the car, they may chuck it and steal another one. In that case we'll sure get them at the oak tree up there on the North Shore Saturday night. What we want you to do is to put that money in the tree at the time we tell you to, so that we will be ready."
"But nobody has ever succeeded in locating these people at the tree," protested Forrester.
"I know," admitted Cahill, grinning, "but O'Connor and me have worked out a plan. We figure that in the past these guys have been able to slip in between the detectives on watch. You see, it's pretty dark in those woods at night. Our plan is going to put a stop to that. It's like this:
"We're going to put a peg in the ground on each side of the tree, back and front. O'Connor will be on one side and me on the other. There'll be a string from each peg running to O'Connor, and the same thing on the other side to me. We'll hold these strings, one in each hand. Now, that completely surrounds the tree, so that anyone approaching will kick into a string. We'll know from the hand the string's in just what direction to look for them in the dark. O'Connor's strings will be A and B, and mine will be C and D. Get the idea?
"If O'Connor feels a tug, he'll yell A or B at me. If I get a feel on one of my strings I'll holler C or D. Get me? Then we'll both make a rush at just the right spot. Believe me, Mr. Forrester, we got them this time. No sneaking up between detectives next Saturday night."
"The idea sounds very good, Cahill," agreed Forrester. "Perhaps it will work. If I don't hear from you in the meantime, what hour do you wish me to approach the tree on Saturday night?"
"We've fixed on ten-thirty, if that is convenient for you, Mr. Forrester," answered Cahill.
"That suits me," declared Forrester.
"And now, we'll be going," announced Cahill, rising. "Thanks for the cigar. As fine a smoke as I've had in a long time."