Lucy Dacus has a pretty, reassuring voice and crafts pleasant folk-pop melodies, which suggests Historian should be easy listening. Not so. The Virginia native’s compelling second album is a startling set of unsparing vignettes exploring damaged or dying relationships, laced with Dacus’ blunt observations. “Am I a masochist, resisting urges to punch you in the teeth?” she muses coolly on “Night Shift,” while “Timefighter” finds her confessing, “I fought time/It won in a landslide.” Starting softly, the songs often build to dramatic crescendos, punctuated by buzzing electric guitars Neil Young would admire. Through it all, Dacus remains sweetly unflappable, her calm demeanor countering the theatrics with the vocal equivalent of a shrug, as if to say, “This too shall pass.” Brutal honesty is rarely this engaging.