Here are two mean and nasty words: Mrs. Cakel
Something has gone wrong in Danny and Calvin's fourth-grade classroom-out of the blue, Mrs. Cakel has transformed from a rampant rule-enforcer to a quiet excuse-accepter. Has she been replaced with an alien? Has she undergone a top-secret personality makeover?
Danny and Calvin decide there's only one way to find out what's really going on—spy. But spying soon leads to a greater mystery filled with dog chasing, jelly-injected donuts, prune butter-included experiments, riddle mania, and more!