Gamer Girl is a book about a girl named Maddy Starr, who is high school student that just moved to a new school because of her parents’ divorce. The book is mainly about how she overcomes her school foes, the Haters, and finds a way to fit in at her new school.

It starts out with Maddy getting ready to go her new school, Hannah Dustin High. Right when she is about to leave, her grandmother (who she lives with) stops her saying that Maddy is dressed like a dead prostitute. So Maddy’s grandma make Maddy change her semi-emo cloth to cloth with unicorns embroidered on it (Maddy’s grandma is obsessed with unicorns). This, of course, would be a nightmare to any high school student, especially if it’s your first day at a new school. When Maddy arrive at the school, she notices a one of the most popular boy, Chad Murray, and instantly falls in love with him. But to Maddy’s horror, her grandma recognize a boy that she used to baby-sit, Billy Henderson, one of the most popular student at Hannah Dustin High and also close friend of Chad. Not only does she publicly hug him, even though he tries to act like he doesn’t know her, but Maddy’s grandma tell everyone near them that she used to remember when he used to wet his bed. This of course humiliate Billy, and making him and all of his friends (minus Chad), the Haters as Maddy starts calling them, Maddy’s sworn enemies.

After a couple of weeks of the Haters torturing Maddy, it becomes Maddy’s birthday. For her birthday her father gives her an online game called Fields of Fantasy. Maddy starts playing the game right after she received it. She creates a character named Allora, and starts playing the game. A week later, when Maddy was playing Fields of Fantasy, she decides to try going against harder monsters. But every time she tried to kill them, they just killed her. Eventually another player named SirLeo comes and helps Maddy defeat the monsters. After SirLeo saves Allora, they start playing and talking together. After awhile, Maddy starts to have feelings for the character SirLeo.

About a week from when she met SirLeo, Maddy decides to start a manga club at her school so she could try making some friends. Half a week later, the first meeting of Hannah Dustin High manga club took place. At the first meeting Maddy met a lot new people that didn’t worship the Haters. So Maddy started to make some friends with the people in the manga club. A couple days after the manga club meeting, Maddy starts to suspect that Matt, a member in the manga club, is SirLeo from Fields of Fantasy. Maddy is horrified to imagine this, even though she would like to be just friends with Matt. But when she talks to him about it, he says that he isn’t SirLeo. But then he helps her figure out who SirLeo really was, and together they find out, to Maddy’s delight/horror, that SirLeo was Chad Murray, the Hater that Maddy had a crush on.

Later that day, on Fields of Fantasy, Maddy confronts SirLeo and tells her that she knew that he was Chad Murray, and he said that she was right. But when, she tells him that she was Maddy Starr, he starts laughing and making fun of her. Maddy is completely crushed.

The next day, at school, Maddy finds out that the Haters stole and vandalized her entry for a manga contest. She goes home and cries over the fact that her hard work was ruined. Her mom convinces her to try taking to some of the pages that weren’t vandalized to contest so that she could at least receive some feed back from the judges.

Maddy goes to the contest, and while she was waiting in line for her turn to present, Chad Murray comes to the contest. Maddy becomes horrified and tries to run away, but she eventually becomes cornered. Chad goes up to her and starts explaining to her that it wasn’t him that was making fun of her, but that Billy was using his Fields of Fantasy file to make fun of Maddy. When Maddy doesn’t believe him, he shows her the manga that she planned to enter in the contest, newly made with the help of the manga club. Maddy is deeply touched and forgives Chad.
The story ends with up Maddy winning the contest and her manga gets entered in the national contest, and Maddy ends up with a whole bunch of friends and a boyfriend.