[1][2] Three years after the events of Specials freed the world from the pretty lesions that forced them to be obedient, society is beginning to settle into a new form.
Every inhabitant has their own feed, obsessively tracks their face rank, and hopes to gain fame and lose their status as an "extra."
Aya Fuse tries to win fame as a "kicker," or journalist, filming stories with her modified hovercam Moggle and posting them for the whole city to see.
One night, accompanied by her hovercam Moggle, she crashes a party in New Pretty Town in the hope of tracking down a group she saw surfing a mag-lev train, a story that she believes will make her famous.
She follows one of the group's members, Eden Maru, out of the party, but they nearly get away when she is distracted by Frizz Mizuno, a more beautiful and far more famous person who compliments Aya.
The group's leader Lai gives Aya a chance to join them, but to do, so she is forced to drop Moggle into an underground lake.
Aya retrieves Moggle and uses him to film her next excursion with the Sly Girls, a mag-lev surfing trip that ends in exploration of the underground room that they discovered.
They plan to return to explore further, but Aya's credibility is ruined by the kicking of a news story about Frizz Mizuno coming to talk to her by her dorm.
Aya is forced to break off contact with Frizz in order to lose fame, which the Sly Girls despise, and the story leaves her disillusioned by the hateful comments of the kickers.
When Aya next meets the Sly Girls, they reveal that they knew she was a kicker, and have decided to allow her to kick the story of the mass driver in spite of their hatred of fame.
Aya kicks her story and becomes instantly famous but is concerned when she receives a message from Tally Youngblood telling her to "run and hide" and is nearly captured by the inhumans while trying to do so.
Eventually, Aya uses her fame to take control of a high-security apartment and waits there until Tally arrives, accompanied by Shay and Fausto.
After deciding Aya, Ren, Hiro, and Frizz would get in the way, Tally, Shay, and Fausto plan to leave them where they were.
Aya especially benefits and becomes the third most famous person in Yokohama after she kicks a story about the Extras that is appropriately called "Leaving Home."
Aya originally wanted to use the Sly Girls as an anchor to bring her miserable face rank up but turned out to save the world in the end.
Frizz Mizuno: A leader of a clique called "Radical Honesty" in which the members must have a brain surgery that gets rid of all deception.
Jai/Kai/Lai and the Sly Girls: The clique did crazy things, but were forced to keep their face ranks down, or the wardens would catch and stop them.
Tally Youngblood: The most famous person in the world, the architect of the mind-rain, and the original protagonist of the Uglies trilogy.
Eden Maru later explains to her the concept of film extras from the Rusties' era, which is the true origin of this term.
In his 2007 New York Times book review, James Hynes described Extras as being "just as thrilling as its predecessors, but it's also a thoughtful novel of ideas, a brilliant parody of the modern obsession with fame.