The Expanse is a science fiction series written by James S.A. Corey (a pen name for authors Daniel Abraham and Ty Franck). It is set in a future where humanity has colonized the solar system and tensions between Earth, Mars, and the Belt (asteroid belt) are high. The story follows a diverse cast of characters, including a detective, a spaceship captain, and a politician, as they navigate political intrigue, interplanetary conflict, and the discovery of a mysterious alien protomolecule. The Expanse combines elements of space opera, noir detective fiction, and political thriller.