*Greg Heffley – Known for his misadventures throughout his school.
* Rowley Jefferson- He is the best friend of Greg. He is also immature and ignorant
* Rodrick Haffley – He is the older brother of Greg. He is the main antagonist and constantly bullies Greg.
The book opens with Greg Heffley saying how embarrassing it is to be having a journal with "diary" on the front and that whoever sees him with it will call him a "sissy". Greg also goes to mention that one day he will become rich and famous but for now he is "stuck in middle school with a bunch of morons". Greg faces too many hardships, including Halloween. As Greg and Rowley go Trick-or-Treating, they anger some teenagers who chase them. They barely escape but manage to get to Greg's grandma's house. The teenagers see them inside and Greg and Rowley taunt them. Not all goes to plan, though, and when they get home and Greg's dad, who was hassled by kids, throws water at them and the water soaks their candy. The Wizard of Oz play is also a hardship for Greg. Patty Farell, who plays Dorothy, is coming on stage, and since Greg is a tree, he thinks he can throw apples at her, but the director takes this part out of the play for health and safety. Mrs. Norton, the music director, tries to make the trees sing an embarrassing song, but on the night nobody sings out of fear and the play is ruined. Greg and Rowley's friendship is starting to fall apart. Greg invents a game where one person throws a football to make the other fall off the Big Wheel; however when Rowley falls off, he breaks his arm. Greg is jealous of the attention Rowley is getting. Rowley is also framed for scaring kindergarteners, when it was Greg wearing Rowley's hat. When Greg confesses, Greg is kicked out, and Rowley is promoted. Rowley also declares himself the owner of a comic strip, Zoo-Wee-Mama, that...