4400 centers on the return of 4400 people who, previously presumed dead or reported missing, reappear on Earth. Though they have not aged physically, some of them seem to have deeper alterations ranging from superhuman strength to an unexplained healing touch. A government agency is formed to track the 4400 people after one of them commits a murder.
A retrospective in the show in an NBC special. Narrated by Jacqueline McKenzie, "The 4400: Unlocking the Secrets" summarises the events of seasons one and two.
