In many ways, Oceanic was the first time the world heard Boston post-metal giants ISIS—realistically, anyway, not literally. It’s a testament to the vastness of this record’s impact and permanence that one could forget the album was preceded by three EPs (1998’s The Mosquito Control EP, 1999’s The Red Sea, and 2001’s SGNL>05) and an album (2000’s Celestial). Compare anything from The Mosquito Control EP to anything on Oceanic. Yes, you can recognize that it’s the same band. But there’s an inescapable feeling that each member of ISIS had, in the years between, undergone some kind of musical spiritual awakening—in the same space, at the same time, instruments in hand, analog tape possibly rolling (this was 2002, after all, and Matt Bayles’ production was as organic as it was expansive). What emerged on Oceanic was something even deeper than the abyssal depths it came from. Post-metal, as ill-defined and nebulous as it still sounds on paper, existed before this release as a disjointed concept at best. Afterwards, a historical axis appeared: With Oceanic, ISIS finished chalking a genre’s outline and colored it in with standards and parameters. Jazz must swing. Punk must rattle. Rock must roll. Post-metal must be an ordeal. Take song length, for example. Almost every track here runs well over seven minutes (and the longest, “Weight,” closes in on 11). There’s a demand for listener patience, investment. The reward? Insistent, consistent momentum set against shifting moods, emotive walls of sound (“False Light”), cinematic sensibilities (“From Sinking”), and cathartically placed riffs—during repeat listens, you’ll find yourself waiting for them with a pleasurable angst, such as when opener “The Beginning and the End” establishes a dualism inherent in its own title that goes on to permeate the entire album circa 4:57. Never have two simple snare flams sounded so portentous. Therein lies a seething theme that exists inside, outside, around, and deeply, deeply beneath the waves of Oceanic: What came before, no matter how seemingly momentous, was simply a horizon masquerading as final meaning. Oceanic is a concept album and the totality of The Red Sea’s intimation; the story of a hopeless man that finds love, has that love destroyed by shocking forces beyond his control, and puts himself out to sea in a final act of slow suicide that echoes his last attempt to remain on dry land. It’s the delivery of an unaware promise to music. When “Carry” washes over you at 3:59 with the closest to tidal insurgence that distorted guitars are ever likely to sound, it is arguably the most defining moment of a record that defined a movement. A movement as unknowable as the bottomless depths suggested by that threateningly simple cover art.