In 2006, Susan Enan gained attention when her tune “Bring On the Wonder” was featured in TV’s Bones. Fans of the Irish folk-pop chanteuse had to wait three years for her debut album — fortunately, the anticipation was more than justified. Plainsong is a work of melancholy beauty, built around Enan’s mahogany-toned vocals and the austere grace of her songwriting. Her lyrics are elliptical, at times almost childlike; her melodies teeter between lullabies and dirges. Tracks like “Monoplain” and “We All Belong Here” paint scenes in grey and blue tones, no less vivid for their brooding quality. The ambiguous journeys revealed in “We All Belong Here” and “Monoplain” are lent depth by echoing pianos and washes of strings. “Moonlight” — the most captivating love song here — mixes its mystery with a touch of gospel. Plainsong is anything but lighthearted; even the comparatively upbeat “Bird” is dark at its core. But these songs are redeemed from sadness by Enan’s emotional honesty and sparse, exquisitely controlled musical touch.