Oliver Zahn, spitball champion and self-declared rule-wrecker of Brightling Middle School, is not a fan of his new homeroom teacher, Mr. Aidact. The guy is sort of stiff, never cracks a smile, and refers to them as “pupils.” The worst part is he catches Oliver before he can pull any of his signature pranks! It’s time for Oliver and his best friend, Nathan, to show the new teacher who’s boss.

But as the weeks go by, they start to realize that Mr. Aidact is not what they expected. He has an uncanny ability to remember song lyrics or trivia. When the girls’ field hockey team needs a new coach, he suddenly turns out to be an expert. He never complains when other teachers unload work on him—even when it’s lunchroom duty and overseeing detention. Against all odds, Mr. Aidact starts to become the most popular teacher at Brightling.

Still, Oliver and Nathan know that something is fishy. They’re determined to get to the bottom of the mystery: What’s the deal with Mr. Aidact?