Open City is the debut novel by author Teju Cole. The story follows the main character, Julius, who is a Nigerian doctor doing his psychiatric residency in New York City. As the story unfolds, Julius takes up walking as a way to distress from the pressures of his job working with his patients. Julius even uses the walks to clear his mind of personal matters, such as a recent breakup with his girlfriend, Nadege. Throughout the novel, the narration of the story does not include any dialogue among the characters, but is told in exposition only.

For Julius, the walks become more than just exercise and a way to clear his mind. He starts to recognize what a true melting pot New York is as far as cultures and ethnicities are concerned. In the face of living in such a diverse city, however, Julius also notices that stark separation that still draws an imaginary line segregating one ethnic group from another.

As Julius walks, he also thinks back to his childhood in Nigeria. His father died when Julius was 14. He is now estranged from his mother. while his father was of Nigerian descent, Julius's mother is white and of German descent, making Julius a mixed race. Due to his mixed race, and light colored skin, Julius feels out of place, even in the worlds where he belongs. As he wanders around the city, black people seem to connect with him, recognizing his African roots.

One of his run-ins with someone he grew up with in Nigeria even reveals that Julius raped her. Subsequently, Julius blocked out the memory of this event and never reveals if he recalls it when his Moji tells him what he did to her.

By the end of the novel, Julius finishes his residency and moves into private practice. It seems as if he has come to terms with some of the events in his life. On the other hand, he never fully addresses some of the other issues to reveal to the reader as to whether the issues are ongoing or resolved.