Middle school: My Brother is a Big, Fat Liar

Middle school: My Brother is a Big, Fat Liar is the 3rd book in the middle school series, and the first book written by Georgia Khatchadorian This book is about Georgia Khatchadorian's first days at HVMS and her struggles to prove that she isn't a troublemaker like Rafe was.

Plot
The book starts with a narration from Georgia, who is ranting about Rafe and how he's a "big fat liar." Then, the story properly begins with the kids getting ready for their first days of school, with Rafe going into 8th grade at Airbrook arts and Georgia going into 6th at HVMS. Rafe tries to warn his sister about HVMS, but she refuses to listen.

When she arrives to her first period, however, Georgia discovers that Hills Village Middle School carries a large prejudice against Khatchadorians, calling her "Rafe Khatchadorian's SISTER" and not giving her any signs of happiness. After getting bullied by a boy who resembles Miller( She even calls him "Mini Miller" for that reason as a joke.) Georgia meets a girl with a loud voice named Rhonda. Then, she has a run-in with a rich girl named Missy Trillin and her cronies Bethany and Brittany( Funny thing is, the book never shows who is who.), who proceed to mock her walk.

After school during a band practice with her friends Nanci, Patti, and Mari, Rafe jokes about their playing skills, suggesting that they change their band name from The Awesomes! to We Stink!( Which sounds more ironic.). Later during dinner when Rafe eats a spicy spaghetti Georgia made, Georgia goes to Swifty's, only to find out Missy's fam is there, too. She tries to get her mom's attention, but Jules is so busy she can't.

After several failed attempts to win Missy and her friends over and awkward run-ins with Rhonda, Georgia abruptly receives a request from Missy to have lunch with them. When she goes out to the school's courtyard to eat, she realizes from a boy named Sam Marks that The Princess Patrol fooled her. Before she can leave, Mrs. Stricker suddenly appears, accusing Georgia of breaking a rule on purpose, giving her and Sam detention. During their time in Ms. Donatello's room, the two develop feelings for each other.

Later during a band practice session, Rhonda tells Georgia that she and her band should join the Battle of the Bands. Later, Georgia catches Rafe reading her copy of The Book Thief. When she tries to get Rafe to return it, he spoils major plot points. Georgia gets her revenge by telling Jules that Rafe was hoarding gum in the toilet. Later, Jules confronts Georgia about her detention, with her saying that it won't happen again.

The next day, Rafe gets payback by dying Georgia's hair green, embarrasing her with Missy. Later, Mini-Miller steals her copy of The Book Thief( Wow, a boom thief stole The Book Thief!), and THEN she gets another detention when Ms. Stricker accuses her hair of being on purpose. During a book report on The Book Thief, the worst comes to pass: Georgia's report messes up, and she gets her first ever D for being Rafe's sister. Enraged by the unfair prejudice placed on her by HVMS, Georgia schemes to prank her brother by fibbing that Jeanne Galleta (Whom Georgia learned was part of the dance committee) wanted to call her. When Rafe looked joyful that Jeanne still knew him, Georgia immediately regretted her prank. However, it was too late, as Rafe discovered that Jeanne never planned to call him.

5 days later, Georgia discovered that Rafe had signed The Awesomes! under the name We Stink up for the Battle of the Bands as an act of revenge. Later, their report cards come in, and Jules becomes ecstatic over Rafe's C-plus, not paying attention to Georgia. (We're even shown a fantasy where on the left page, it show Rafe succeeding, and Georgia on the right being mocked and scorned. It even shows that ALL of Georgia's classes have D's.)

Later, the siblings discover that Grandma Dotty had gotten rid of their stuff and beds without telling them. To get their stuff back, they convince Dotty to host a yard sale so they can save their items. During which, Rhonda and Sam appear and listen to a band practice Georgia performed with her friends. Unfortunately, so did Missy, mocking Georgia again, leading to her saying that Rhonda wasn't her friend.