Richard's day gets off to a bad start when he has to wear too-big purple corduroy pants to school. Although it's Richard's turn to lead the Pledge of Allegiance and to hand out the mealworms that Mrs. Zookey's class is going to study, those purple pants keep getting in his way. Richard tells his classmates that the pants are a gift from his aunt and uncle, who are space aliens from the purple planet Pluto. After he names one of his mealworms Uncle Ken, the real Uncle Ken shows up in Mrs. Zookey's classroom, knock-knock jokes, too-loud laugh, and all. Richard has some explaining to do, but a plan for Silly Clothes Day and a surprising rapport with his uncle make it a good day after all.