Yumi is a Fillmore! character, and an X Middle School student.
Role in the series
A year before, Yumi gets the idea of making a virus to reveal secrets of the Haves, or the Popular Kids, to show that "everyone is ugly".
Her friend Gladys gets scared of virus and what the project is doing to Yumi, and over the summer becomes Alexis Bixby, a popular kid at X School in hope that Yumi would not find her. However, Yumi does, and threatens to reveal to her new friends that she is really a make-over computer nerd unless Gladys helps finish the "Electric Haircut" project.
She goes into the school's computer system and removes every trace of Alexis. Fillmore talks some scene into her, and she stops her virus. When Jonah, Gladys, Yumi and Maryanne as a group enter the Safety Patrol -- she remarks that Principal Folsom is talking to her parents and "if she winds up with detention until high school", she would be lucky. She tells Fillmore that she said "sorry" to Gladys and then to him, and then "Thanks" for "Making a good argument."