"You never can tell," remarked his father. "It may turn up some time. Perhaps the thief will get himself into trouble yet. Keep your ears and eyes open. And now, if you don't mind, I have some reports to write--" Frank and Joe took the hint and left their father to his work. But although they talked long into the night on possible ways and means of recovering Chet's car, they were able to devise no plan for tracing the thief. And through the week that followed there were no further clues. Chet had given up all hope of seeing the roadster again. "I sure miss the old bus," he told the Hardy boys after school on Friday afternoon. "I have to take my chances on catching rides in and out of town now. Why, last night I walked half way home before a car came along and gave me a lift." "Saturday will be a pretty dull day for you now." "You just bet your sweet life it will be dull! Nothing to do but sit around the farm." "Better come with us to-morrow," suggested Joe. "A bunch of us are going fishing up near the dam. You can meet us at the crossroads near Willow River." "Good idea!" said Chet. "What time?" "Ten o'clock." "Fine! I'll be there. Gosh, I see where I get a ride home. There goes a hay wagon, and it's heading right for the next farm." A long wagon rumbled slowly toward the boys. A lean and solemn farmer perched on the front seat, half asleep. The horses dawdled along. "That's Lem Billers--the laziest man in nine counties," said Chet. "Watch me have some fun with him." Chet took from his pocket an automobile horn. He had originally bought it for the roadster but had not had time to install it before the car was stolen. The horn was of a new type, very small, yet it had a particularly raucous shriek. The Hardy boys grinned as they saw Chet step out into the road and swing himself lightly up on the back of the wagon. Mr. Billers was bringing some supplies back to the farm and Chet was hidden from view by a bag of flour. As the wagon rumbled past, Chet sounded the automobile horn. It shrieked sharply and insistently. Mr. Billers, being a lazy man, did not even look behind. He simply tugged lightly at the reins and the horses edged over to the side of the road. Having heard the horn, Mr. Billers expected an automobile would pass. But when no car flashed by he turned indolently in his seat and looked behind. The roadway was clear. There was not an automobile in sight. He did not see Chet, doubling up with laughter, on the back of the wagon. He gazed doubtfully at the Hardy boys, who were standing at the curb, trying to conceal their smiles. "Could 'a' swore I heard a horn," grunted Mr. Billers. Then he tugged at the lines and brought the horses into the middle of the road again. Instantly the horn shrieked again. This time it was even louder and more insistent than before. It seemed that an automobile was right behind the wagon, clamoring to pass.