First grader Junie B. Jones is determined to win the grand prize at wealthy classmate Lucille's Easter egg hunt--a playdate in Lucille's heated swimming pool.
Through a misunderstanding, Junie B. thinks that her new baby brother is really a baby monkey, and her report of this news creates excitement and trouble in her kindergarten class.
With Halloween approaching, Junie B. needs to find a costume that will scare off the real witches and ghosts that she believes will be out on the holiday.
Excitable Junie B. Jones manages to find trouble both before and during a trip to Hawaii and records each incident in a photo journal given to her by her teacher.
Junie B.'s journal entries start with Room One's stomach virus excitement, the first-grade Columbus Day play, and getting the part of the Pinta, the fastest ship.