"Come over here," whispered Harry. "You can look through this crack between two boxes. It's right near the cash drawer, and you can see the bill when George makes change for it."
Frank crept up to make an observation, and as the store boy took the bill from the man, and began making change, Frank could not hold back any longer. He saw that the bill was the same kind that had fooled him. It was Confederate money, and utterly worthless.
"Don't give that man any change!" cried Frank. "That's bad money!"
CHAPTER XXII
HAPPY DAYS
Bert and Harry were so surprised at Frank's sudden call, that, for a few seconds, they did not know what to do or say. George Smith, the boy in the store, was also startled. He stood with the bad twenty dollar bill in his hand, wondering where the warning voice had come from. And then Frank showed how quick he could be.
"Hurry up!" he whispered to Bert and Harry. "One of you slip around and lock the front door, and the other one lock the back. Then we'll have this man trapped, and maybe I can make him pay back the money he got from me. Quick!"
"I'll go to the front door!" exclaimed Harry.
"And I'll lock the back one!" said Bert.
The man, who had heard Frank's call from behind the pile of boxes, must have known something had gone wrong with his plan to cheat.