24 is a serial drama starring Kiefer Sutherland as Jack Bauer about the efforts of the fictional Counter Terrorist Unit to protect the United States from terrorist plots. The episodes take place over the course of one hour, depicting events as they happen, in real time. To emphasize the real-world flow of events, a clock is prominently displayed on-screen during the show, and there is a regular use of split screens, a technique used to depict multiple scenes occurring at the same time.

Each episode typically follows Bauer, officials in the U.S. government, and the conspirators behind the events of the day, often simultaneously. 24 is known for employing plot twists which may arise as antagonists adapt, objectives evolve or larger-scale operations unfold. Stories also involve interpersonal drama, delving into the private lives of the characters. As part of a recurring theme, characters are frequently confronted with ethical dilemmas. Examples of this are a bombing in Season 2, which can only be prevented by blowing Bauer's cover, and an ultimatum in Season 3, in which a terrorist agrees not to carry out an attack if a high-ranking CTU official is killed. Season 4 is also notable for a scene in which two men—one of whom possesses crucial information—are dying in a room with only one surgeon.