"Intervention" is a typically intense track from Arcade Fire's Neon Bible. It's a good tune, so no complaints. For the B-side, Arcade Fire take "Ocean of Noise," the prettiest song on the same album, and hand it off to their pals in Calexico, who do their own version of it. Calexico do Arcade Fire proud. Don't get all snippy, irate indie-rockers -- cover versions are groovy and Calexico's is fantastic.