Shevek, citizen and acclaimed physicist of the world Anarres, believes that he must free his people from the walls that they have built around their anarchist state, blocking out all other worlds. A freethinker and believer in the power of revolution and the individual's right to self-rule, Shevek must risk all to discover the truth about the land that his people escaped from, Urras.

But all is not as he believes on the glittering world of Urras. Coddled within the ivory towers of its university, Shevek is prohibited from seeing the real world of Urras, the world of the poor and indigent from which his people came. Although shunned by his Odonian society for his cutting-edge theories, the Urrasti hold him captive for his knowledge of the General Temporal Theory, a theory that could bring the Urrasti all the power and fortune they desire.

Aware that he has only traded one set of walls for another, Shevek must make an even more dangerous journey if he is truly to succeed in his ultimate mission of fostering understanding and true brotherhood among the races. Enlisting the aid of sympathetic Urrasti and aliens from Terra and Hain, Shevek succeeds in evading the propertarian Urrasti and shares his knowledge with the universe. For it is only when there is a true understanding, that he can finally return home to a new world.