Mr. Henshaw sends Leigh a postcard from Wyoming, so Leigh responds with a letter. Leigh shares with Mr. Henshaw that Mr. Fridley raises the flags each day at school, and one day he raised the California flag upside down. When Leigh pointed out the mistake, Mr. Fridley invited him to help. Now each day he helps with raising the flags and enjoys not being alone at school when he arrives so early. In his postcard, Mr. Henshaw suggests Leigh keep a diary, and he says he’s thinking about trying it.

Leigh buys a composition notebook to serve as his journal and prints a warning on the cover to snoopers. However, Leigh admits to Mr. Henshaw that he isn’t sure how to begin journaling.

Mr. Henshaw responds with another postcard and suggests that Leigh treat his diary like a letter and pretend to write to someone. Leigh admits that he used to write letters to his dad but stopped because he never responded. Leigh decides he will pretend to write to Mr. Henshaw in his diary.