METALHEADS CAN BE stubborn traditionalists—even conservative at times. Fans often consider a band's pivotal or breakthrough album as a template, a foundation upon which the band must build all other achievements. It's as if that monumental album becomes a cage, and if the band tries to stick even a limb through the bars, fans will instantly cross their arms, shake their heads, and say, "Where do you think you're going?"

With their third full-length, Sister, In Solitude have broken out of their cage and given the proverbial finger to all naysayers. Normally this would spell disaster, but the consequences for these Swedes' liberation should prove slight, because Sister is a flawless, fantastic record that will no doubt top end-of-year lists in a few short weeks.

Vocalist Pelle Åhman says taking a leap with their sound was out of their control. "We were just doing what was urgent at the time. The development of our sound is something completely natural and logical. The expression evolves simultaneously with the persons involved with it. To me, this is something fundamental in any creative work."

In Solitude's first two releases, In Solitude and The World. The Flesh. The Devil, are both solid, evil heavy-metal records. While highly regarded, they caused the band initially to be pegged as derivative of titans like Mercyful Fate and Iron Maiden. Åhman doesn't have the vocal range of King Diamond, but he has a theatricality to his style that warrants the comparison. Henrik Palm and Niklas Lindström's bleak, dual, harmonized guitar riffs are most definitely Maiden-esque, pointed more toward the dark side of the spectrum. With Sister, In Solitude haven't completely turned their backs on their previous influences, but they've certainly trimmed them down quite a bit, leaving room for more introspective elements.

"I'm not sure if the writing process in itself has a transcendent nature while it's happening," says Åhman, "but a lot of revelations come once it is processed and understood to some degree. We are reaching for a very visceral place with our music, which makes things very emotional for us."

Sister has only eight tracks, but it instantly comes off as a much deeper, thicker album than its predecessors. The first track, "He Comes," is an acoustic-driven, swelling chant that sounds like it should be sung by a coven of witches over a boiling cauldron. The rest of the album, with some tracks heavier than others, all have a brooding, gothic feel, making Sister sound like one part Mercyful Fate's Don't Break the Oath blended with four parts of the soundtrack to The Lost Boys.

In Solitude has gone deeper into themselves and their music, looking beyond their influences to discover where their sound should really be coming from. Wherever that is, it must be a grim place. But in spite of Sister's forbidding feel, Åhman makes it sound beautiful.

"I constantly find important things for lyrics in the details of existence that accentuate things spiritually for me," Åhman says. "That can be anything from a line in a book to the way a stone splashes the surface of water."