24 is an American dramatic action/thriller television series co-created by Joel Surnow and Robert Cochran. It premiered on Fox on November 6, 2001.24 centers on the (fictitious) Los Angeles branch of the U.S. government's "Counter Terrorist Unit" (CTU). The series is presented in real time format; each one-hour episode depicts one hour's worth of events, and each season is a twenty-four hour period in the life of protagonist Jack Bauer (played by Kiefer Sutherland), a CTU agent. The first six seasons of the show are set in Los Angeles and nearby locations – both real and fictional – in California, although other locations have been featured. The seventh season is set primarily in Washington, D.C., rather than Los Angeles. The eighth and final season shifted locations to New York City.

The first three seasons aired over a complete television season between October and May, taking hiatuses between blocks of episodes. Beginning with the fourth season, Fox scheduled 24 to premiere midseason, with a new episode airing every week. Season seven was due to premiere on January 13, 2008 but was delayed an entire year due to the 2007–2008 Writers Guild of America strike. Fox aired a two-hour "prequel" movie, 24: Redemption, on November 23, 2008 that bridges the gap between seasons six and seven. Season seven premiered on January 11, 2009, with a four-hour premiere over two consecutive nights. Fox announced that the eighth season would be the final season of 24, with the series finale airing May 24, 2010. With the conclusion of the eighth season, 24 aired a total of 192 episodes and the 2-hour television movie, 24: Redemption.