When Frank and Joe Hardy arrived home that evening they met Hurd Applegate just leaving the house. The man tapped the steps with his cane as he came out and when he met the boys he gave them an abrupt and piercing glance. "Good day!" he growled, in a grudging manner, and went on his way. "He must have been asking dad to take up the case," said Frank to his brother, as soon as Hurd Applegate was out of earshot. They hurried into the house, eager to find out more about the robbery, and in the hallway they met Fenton Hardy, who had just seen Mr. Applegate to the door. "I hear the Tower Mansion was robbed," said Joe. Mr. Hardy nodded. "Yes--Mr. Applegate was just here. He wants me to handle the case." "How much was taken?" "Quite curious, aren't you?" remarked Mr. Hardy, with a smile. "Well, I don't suppose it will do any harm to tell you. The safe in the Applegate library was opened. The loss will be about forty thousand dollars, I believe." "We heard it was over a hundred thousand!" exclaimed Joe. "Rumors always exaggerate. Forty thousand dollars is the figure Mr. Applegate puts it at. And it's quite enough, too. All in securities and jewels." "Whew!" exclaimed Frank. "Quite a haul! When did it happen?" "Either last night or this morning. He did not get up until after ten o'clock this morning and he did not go into the library until nearly noon. Then he discovered the theft." "How was the safe opened?" "It was either opened by some one who knew the combination or else by a very clever crook. It wasn't dynamited at all. I'm going up to the house in a few minutes. Mr. Applegate is to call for me." "Can't we go along?" asked Joe eagerly. Mr. Hardy looked at his sons with a smile. "Well, if you are so anxious to be detectives, I suppose it is about as good a chance as any to watch a crime investigation from the inside. If Mr. Applegate doesn't object, I suppose you may come along." In a few minutes an automobile drew up before the Hardy home. Mr. Applegate was sitting in the rear seat, resting his chin on his cane. When Mr. Hardy mentioned the boys' request he merely grunted assent, so Joe and Frank clambered into the car with their father. They were tremendously excited at the prospect of being "on the inside" in the mysterious case. While the car bowled along over the city roads toward the Tower Mansion that was gloomily silhouetted against the sky, Mr. Hardy and Mr. Applegate discussed the robbery. "I don't really need a detective in this case," snapped Hurd Applegate. "Don't need one at all. It's as clear as the nose on your face. I _know_ who took the stuff. But I can't prove it." "Whom do you suspect?" asked Fenton Hardy. "Only one man in the world could have taken it. Robinson!" "Robinson?" "Yes. Henry Robinson--the caretaker. He's the man." The Hardy boys looked at one another in consternation.