"I know my soul was born to do some cool things," testifies AK over the wood flute-and-maracas loop of "Rain Dance (Phase One Intro)". The Underachievers, his duo with Issa Gold, practice the kind of esoteric mysticism that once flourished in some far-flung corners of '90s rap, from the feverish jabberwocky of Leaders of the New School’s T.I.M.E.: The Inner Mind’s Eye to the pan-African zealotry of X-Clan’s To the East, Blackwards, and the backpacker bohemianism of Zion I’s Mind Over Matter, Mystik Journeymen’s The Black Sands Ov Eternia and Abstract Tribe Unique’s Mood Pieces. It’s an ethos that largely dissipated by the end of that decade as rap moved on. But the Underachievers have not only revived it, they’ve stuck with their spiritual bent through four projects, including 2013’s revelatory Indigoism, last year’s uneven but satisfying Cellar Door: Terminus Ut Exordium, and now Evermore: The Art of Duality.

At first, Evermore appears to offer more of the same, as they rap about being miseducated in school, dabbling in street hustles, and feeling alienated from society. "We lost in this world, but it’s hard to relate," says AK on "Chasing Faith". They strive to use their experiences to educate others through hip-hop music, celebrating the use of "natural" herbs such as marijuana and ‘shrooms, but acknowledging that they’ve struggled with harder substances. They underline the importance of their metaphysical lessons by acknowledging in "The Dualist" that "We all sin."

AK and Issa Gold complement each other. Vocally, AK has a more sour tone and a barking delivery that sounds like he’s dispensing real talk. Issa Gold has a mid-range baritone that lightens when he gets excited, as if he can’t wait to finish rapping one line and start the next. Both are strong lyricists, but for much of Evermore, they repeat the same themes again and again. The perils of mental illness are frequently noted; mainstream religious dogma, school indoctrination, and the banality of social media and Western pop culture are repetitively disparaged.

These observations are delivered over serene production. "Shine All Gold" matches an acoustic guitar loop to a bass drum bounce, then closes with an ambient techno beat. The next two tracks, "Chasing Faith" and "Star Signs", pick up that downtempo thread and build backgrounds full of melancholy and yearning. "The Dualist" breaks the holistic spell with the kind of mid-'90s boom-bap classicism on which the Underachievers and other Beast Coast artists built their reputation. The warm electric keyboards and synthesizers of "The Brooklyn Way" make for a particularly glorious peak. "Hands up if you live for love," chants Issa Gold.

For much of Evermore, the Underachievers spin in their spiritual axis, until a series of tracks near the end break the heavenly trance with jarring abruptness. Trap orchestration creeps in on "Take Your Place" as Issa Gold warns, "Don’t fuck with the snakes," and AK adds, "Really pop up on a nigga blocka/ If he think he hotta ‘cause a nigga conscious/ Got to keep a chopper just to cease the nonsense." The duo descends into a hellish inferno until they reach the ninth circle of "Allusions". "Got a bitch in the Bay that loves the ‘shrooms/ She be screamin’ AK when I shove the broom," brags AK. Issa Gold adds, "Smoking fuego with your dame/ Been like a whole 20 minutes, can’t front, nigga still don’t know her name /30 minutes later, had my pinky in her brain/ She like, I thought you was different, all of you rappers just the same/ She ain’t complain."

The latter songs throw everything that precedes it into doubt. Are the Underachievers just rap dudes lusting for weed, bitches, and cash like everyone else? They’re obviously aware of the contradictions, but Evermore: The Art of Duality places these adventures in a present-tense context. Perhaps they’re simply acknowledging their flawed humanity. Just as likely, they don’t yet realize that their perspectives on sex and violence can be as tough to break as the mental prisons that damaged their troubled youth.

The Evermore journey is an engaging one, but it would have slid into a new age torpor if not for the spate of ugliness near the album’s end. The coarse "Generation Z" shenanigans give the earlier "Chasing Faith" added urgency. We now know why the Underachievers strain to ascend their earthly selves. "I done came far, still got a lot further to go," raps Issa Gold on the final track, "Unconscious Monsters (Evermore Outro)". "Trying to leave a mark by giving everything that I know."