“It will be wonderful if we can have Dad back with us again,” said Perry. “Although it won’t be quite the same. He’ll be under a cloud as long as this mystery isn’t cleared up. And of course Mr. Applegate won’t employ him any more.”

“All the more reason why we should get busy and clear up the affair,” returned Mr. Hardy. “You boys can help.”

“How?”

“By keeping your eyes and ears open and by using your wits. That’s all there is to detective work.”

“Well, you can just bet that if it will clear Slim’s dad we’ll be listening and looking for every clue there is,” Joe assured his father.