The title of the story identifies the incident that animates the action of this masterful piece of short fiction. Dave Sexton, together with five of his classmates, climbs a neighbor’s cherry tree to capture a lizard while on a field trip with his high school biology class. The tree is broken and the six boys must pay for the damage. Unfortunately, Dave Sexton is unable to come up with his dollar. The principal, Professor Herbert, contributes the money for Dave but makes him stay after school to work off the debt. It is at this point that the story begins.

Dave would rather take a whipping than stay after school, because he must help his father with the farm chores. Professor Herbert, however, believes that Dave is too big to be punished in this fashion. When Dave gets home two hours late, Luster Sexton, Dave’s father, is furious with his son, as well as with the high school principal, modern education, and society in general. Luster vows to go to school with Dave and put a stop to such foolishness as “bug larnin’.” He declares, “A bullet will make a hole in a schoolteacher same as it will anybody else.” Before Luster leaves with his son the next morning, he straps on his gun and holster.

Naturally, Luster causes a commotion in the school with his rustic ways and his revolver. He confronts the principal and, after placing his gun on the seat beside him, demands an explanation. Professor Herbert is taken aback and then explains that he had no other choice than to punish Dave in the way he did. He also tells Luster that education has changed since the days when he attended school. When Herbert offers to show Luster what really goes on in high school, he accepts, accompanying the principal on an extended tour for the whole day, and eventually showing up in his son’s biology class, where he sees germs under a microscope for the first time.

In the end, Luster understands that the world has changed considerably from the time when he was a boy, and that there is a need to learn more than “readin’, writin’, and cipherin’.” When Professor Herbert excuses Dave from the two hours of work yet remaining from him to pay his debt, Luster will not hear of it. So changed is his attitude that he volunteers to help his son sweep the school, insisting now that Dave get all the education he can.