Six years ago, Jessica Lea Mayfield was a precocious teenager singing simple, sullen country songs about hitting rock-bottom. On her third LP (and first without the Black Keys' Dan Auerbach producing), she's grown into a world-weary alt-rock dreamer. The set opens with the grungy "Oblivious" and its grown-up passive aggression: "I could kill her with the powers in my mind/But I'm a good humanitarian." Elsewhere, between tremulous indie textures and slow-core plucking, Mayfield renounces her own childishness ("Unknown Big Secret") and regrets past indiscretions ("Party Drugs"). Her sweet and sweltering guitar playing and forked-tongue revelations are exactly what 24 should sound like.