The end of the world, according to the Roots, looks a lot like post-World War II Europe, only worse. Shot in dusty, dulled, almost-black-and-white, the band’s video for new song “The Fire” is a nightmarish five minutes of kidnapping, cannibalism, and murder, all set to the track’s haunting groove and John Legend’s vocals: “You don’t say good luck / You say don’t give up.”