Bored, Tom releases a tick he has captured on his desk. He lets Joe Harper, seated next to him, play along in a game with the tick. Tom can't resist cheating. The boys bicker, attracting the master's attention, who slaps them both on the back.
Tom devises yet another distraction to avoid what his adult supervisor would have him do. Even though the game he invents requires no skill, he is still competitive about winning it.
When the students are let off at noon, Tom arranges with Becky to meet back at the school room. There they flirt further, and after Tom helps Becky draw a picture, he asks her to be engaged to him.
Tom's ideas about courtship are based on what he has read in books. He lacks the insight to realize that his courtship should be prolonged, lest he too quickly fall for another girl. After all, he only just recently fell for Amy Lawrence. Twain's depiction of Tom's wayward heart offers lighthearted satire of adults who too quickly fall in love.
To confirm their engagement, Becky says she loves Tom. They kiss. Afterwards, Tom explains more about faithfulness, accidentally spilling his former engagement to Amy. Becky is upset to learn that Tom has loved another. To stop her crying, Tom offers her "his chiefest jewel, a brass knob from the top of an andiron." She throws it down on the floor.
Tom fails to recognize his own selfish behavior, and can't understand what he sees as Becky's irrational response. He still expects her to be so in love with him that she would want one of his treasures, a glorified doorknob. Becky's extreme reaction to Tom's stupid behavior is again satirical, with Twain presenting a stereotypical view of women as hysterically jealous.
Tom storms off, not returning to school after lunch, leaving Becky heartbroken.
Rather than face further disappointment, Tom leaves the scene. His behavior does not appear nearly as gallant as his imagination would have it.