Ramona Quimby has a vivid imagination and alot of spunk, which sometimes earns her the rather unfair reputation of being a bit of a pest. Of course, she doesn't mean to be a pest. Circumstances conspire with each other to make her seem that way. Now that her father has gone back to college, and her mother is working full time, it's been decided that Ramona is grown up enough to make her own way to school (after all, she is eight). Ramona is going into third grade, and is also going to a new school, Cedarhurst Primary, where she and her friends will be the oldest kids there. Because her sister Beezus is going into high school, Ramona is going to be riding the school bus every day.
To Ramona, this new found responsibility is a great thing. She loves the changes and is excited to start a new school and to ride the bus. At least, she's excited until a boy on the bus steals her brand new eraser. She nicknames the boy "Yard Ape" but surprisingly the two end up being friends because they are each just as spunky as the other.
Third Grade has its definite pluses and minuses. The best thing about it in Ramona's opinion is Silent Sustained Reading. Ramona loves to read, and because it's "silent reading" she is able to concentrate on the book she is reading without any distractions from the noisier kids. The biggest minus is her teacher, Mrs Whaley. Ramona can't be certain, but she thinks that Mrs Whaley doesn't like her very much.
At lunchtime, Ramona cracks her hard-boiled egg on top of her head only to discover that her mother put the wrong egg in her lunchbox. She ends up with egg on her face - literally. With raw egg dripping down her face she is sent to the secretary's office, to get cleaned up. Mrs Whaley is already in the office and Ramona overhears her telling the secretary that she doesn't like Ramona because she is a nuisance and a show-off. Ramona is very upset and even Yard-Ape can't seem to cheer her up, or make her feel better about herself, because he can't make her un-hear it.
Things get worse; Ramona throws up in class and the secretary calls Mrs Quimby to take her home. This means her mother has to leave work to pick her up which is something Ramona knows she is not meant to ask her mother to do.
After school, Ramona goes to grumpy old Grandmother's house whilst she waits for Beezus to pick her up. On the face of it this sounds fun, but it's not; Howie gets to ride his bike outside in the street and play with his friends, but Ramona has to take care of Willa Jean, who is spoiled and obnoxious and wants to play Uncle Rat all the time. Whenever Willa Jean misbehaves, which is often, Grandmother always seems to blame Ramona anyway. When Beezus does get home, Ramona diligently helps her to prepare dinner but she doesn't have to look after Willa Jean at all because she can use doing homework as an excuse. It's not easy for the Quimby household with only one wage coming in, but Ramona is determined to make it as easy as possible for her family to be happy and for things to run smoothly, but luckily, with true Ramona style and spunk, she is able to find some creative ways to do just that.