"What is it?" asked Bart.
"We ought to get right to work and play a trick on the Upside Down boys. We haven't much time left this term."
"Good!" exclaimed Fenn. "That's what I say. But what shall we do?"
"I think I have a plan," said Frank. "You know Judge Benton's son belongs to that crowd."
"Does he?" asked Ned, for this was news to himself and his two chums.
"Yes. I didn't know it until a little while ago. I was talking to the judge about—er—about some private matters—and he asked me if I was going to the dance. I asked him what dance, and he said the one the High School boys were getting up. That was the first I'd heard about it, but I pretended to know a little bit, and I learned that the Upside Down boys, of which his son is a member, are planning one for Saturday night in the hall over the drug store. Young Benton had to ask his father for some money to help pay expenses, so that's how the judge knew. Now what's the matter with us getting even with them for what they did to us, by playing some trick at the dance."
"Are there going to be girls there?" asked Ned.
"Of course."
"Then I think I know something that will break up the dance and not harm any one either," Ned replied.