After spending the better part of a decade in the musical minor leagues, Death Cab for Cutie went pro with 2005′s Plans, a record whose optimism and bright, Technicolor sound gave the band enough leverage to enter the mainstream. “Soul Meets Body” became their biggest rock single to date, but it was Ben Gibbard’s delicate love song, “I Will Follow You Into the Dark,” that earned the quartet a Grammy nomination and legions of new fans. Some bands might have taken a cue from that success and resigned themselves to a career of acoustic ballads, not unlike the Goo Goo Dolls’ transformation in the mid-’90s. But Narrow Stairs roughs up Plans’ bright palette with something starker, more harrowing, and altogether darkened by Gibbard’s blues. No longer crooning about love or his desire to embrace all of Manhattan, the frontman lives inside his own troubled head on these 11 tracks — or at least the heads of the characters he conjures up with ease, like some music-minded novelist with a knack for pop melodies and witty observations. There’s “Cath,” an ill-married girl who “holds a smile like someone would hold a crying child,” as well as the creepy stalker in “I Will Possess Your Heart,” who simply demands that his intended lover give him the time of day. Elsewhere, Gibbard sings about a friend’s recent heartbreak by referencing her bedroom furniture (“Your New Twin Sized Bed”), offering up his concern — if not quite his help — while the band conjures up a lazy summer’s day beneath him, layering gauzy keyboards with chiming guitar riffs. This sort of contrast between music and text plays an occasional role on Narrow Stairs, with songs like “No Sunlight” and “Long Division” pairing somber lyrics with upbeat, happy orchestration. But the album largely paints itself as the darker, mysterious cousin to Plans — raw rather than polished, heartbroken rather than optimistic, enigmatic rather than energetic. Gibbard strings his words together with an army of free-flowing “ands” and “buts”, and the resulting lyrics — long, uncoiling sentences with no clear end — mirror his characters’ desperatation. Narrow Stairs is far from desperate, however, and the album’s willingness to steer Death Cab into unfamiliar territory (or, to reference an earlier lyric, “into the dark”), is by far its biggest strength. – Andrew Leahey