If Frances the Mute were a horror movie (and with its ominous imagery, that's not much of a stretch), it would thrive on gotcha moments, those sudden shocks that make viewers spill their sodas or otherwise soil their seats. In the past, the Mars Volta has bungled this approach, either administering adrenaline overdoses or inducing terminal boredom during the expository instrumentation. Frances, though, makes glacial momentum shifts compelling, mostly because the payoffs pack Titanic-meets-iceberg impact. The song segments hiding in these epic, four-part suites recall Talking Heads' polyrhythmic punk tribalism and Led Zeppelin's arena-sized mysticism. And like King Crimson, its clearest progressive progenitor, the Mars Volta embraces symphonic string arrangements, slow-winding guitar squiggles, lost-in-the-mix choral accents, and spasmodic signatures. But whereas '70s art-rockers aligned themselves with classical literature, the Mars Volta makes its own mythology. That its inscrutable bilingual lyric sheet offers no easy interpretation of its inspirations only enhances the experience. True terror always comes from what's not shown.