There are few shades of grey in Flyleaf’s world — this Christian combo confronts sin and redemption in the starkest and most apocalyptic of terms. On their sophomore album Memento Mori, the Texas quintet clinches its hold on Gothic-tinged nü-metal while deepening its lyric thrust. This time, singer Lacey Mosley plays down her penchant for screaming, though her intensity remains undiminished. The band’s fervent faith is caught in bold colors, whether the song offers paeans to God (“Beautiful Bride”) or expresses an aching need for salvation (“Again,” “In the Dark”). As before, the sense of desperation embodied in Mosley’s voice is Flyleaf’s most distinctive feature — she’s particularly arresting when railing against evil and corruption, as in the scathing “Swept Away” and “The Kind.” Memento Mori’s sound is dark and astringent, with “Treasure” adding a dreamy touch and “Chasm” moving with a near-swagger. Guitarists Sameer Bhattacharya and Jared Hartmann achieve some elegant textures amidst the overall blistering sound of the album.