Moving Mars has two characters of major importance to the novel's plot and themes, although one is dominant as narrator. She is Casseia Majumdar, first cast in a role of student protester at a Mars university in the year 2171.

Casseia's family is conservative; her third uncle founded Majumdar Binding Multiple, one of the extended-family syndicates that direct the resources of Mars in this era. In spite of family disdain for political activism — the Binding Multiples rule in disorganized fashion — Casseia clings to a study of Martian state theory and "govmanagement." Themes of maturation and identity emerge through the character of Casseia, whose personal story parallels the political coming-of-age of Mars.

Casseia soon casts off her student opposition to the 2171 "Statists," proponents of Martian unification. After participating in a diplomatic mission to Earth, she begins to rise in government until she is Vice-President, then President of the...