Extras is the fourth of Westerfeld's series set in a future world following government-sponsored manipulations such as population control and culture integrations. Most characters have submitted to mind- and/or body-altering surgeries earning them their categorizations such as "pretties", "bubbleheads", and "Radical Honesty" clique members. This story builds around Aya, a 15-year-old "extra" yearning to raise her "face rank" by "kicking" a fabulous story. When such a story falls into her lap she faces choices about personal safety, honesty, loyalty, and bravery as she uncovers a story much bigger than what she thought.
Language
No cursing.
Potentially offensive words include "sucked" and "crap".
Sexual Situations
Two main characters share brief kisses.
Violence
Characters are bruised and battered by fists and collisions during fights with their enemies and while escaping via hoverboards.
Other-worldly characters are capable of sedating their enemies with poisonous "needle fingers".
Suspected weapons are blown up in order to destroy them.
Drugs/Alcohol
Alcohol is served at a party with minors.
A 15-year-old main character drinks champagne.
Race Issues
The novel takes place in Japan, but explains that most races and cultures have been mixed.
Genetic beauty is disregarded as most humans have surgery at 16 to make them "pretties" instead of "uglies".
Religion
A main character states, "Gods are so last year." when referring to religious cliques.
Politics
World government has induced population control, mind-control, a money-free economic system and many secrets.