Angel is an American television series, a spin-off of the television series Buffy the Vampire Slayer. The atmosphere of the show was darker. The series was created by Buffy's creator, Joss Whedon in collaboration with David Greenwalt, and first aired on October 5, 1999. Like Buffy, it was produced by Whedon's production company, Mutant Enemy. The show details the ongoing trials of the vampire, Angel, who has his human soul restored to him by gypsies as a punishment after more than a century of murder and torture of innocents, leaving him tormented by guilt and remorse. During the first four seasons of the show, he works as a private detective in a fictionalized version of Los Angeles, California, where he and a variety of associates work to "help the helpless" and to restore the faith and save the souls of those who have lost their way. Typically, this involves doing battle with evil demons or demonically-allied humans, primarily related to the law firm, Wolfram & Hart. He also has to battle his own demonic ghosts.