Flannery O’Connor, a writer familiar with the weight of darkness, described the look of a dying woman as one “of a person whose sight has been suddenly restored but who finds the light unbearable.” The music of Finnish singer-songwriter Mirel Wagner speaks to a similar knowledge: that light and dark cannot exist without each other, that one is not inherently more valuable than the other, and that the combination of the two is what measures a life.

As is implied in the title of her second album, When the Cellar Children See the Light of Day, Wagner makes haunting, revelatory music for hidden places. Her gentle, unembellished voice and bluesy acoustic guitar are as simple and superficially soothing as lullabies at first listen, but her subject matter is decidedly not for children, and the sleep toward which she sings is not temporary.

Opening track “1 2 3 4” starts with the line, “1 2 3 4 / What’s underneath the floor?” — and perfectly frames the album’s mission to exhume what usually stays buried. The song follows in the footsteps of “No Death,” a love song housed in necrophilic terms from Wagner’s 2012 debut. (Which should also provide a hint as to what lies underneath the floor.) To the same degree that she sings for hidden places, Wagner sings for the dead; as a songwriter, she seems interested in digging past the heart of any matter and into bone. Floorboards can’t keep secrets, death can’t stop love, and squeamishness won’t save you from knowing what you’d rather not know.

“I got a big big heart and lots of love, and it’s hard,” Wagner sings later in “1 2 3 4.” In the same way that Hurray for the Riff Raff confronted the murder-ballad tradition in this year’s “The Body Electric” by singing to a ballad’s victims, Wagner aligns herself with subjects that are forgotten or ignored, intentionally or otherwise. Having a big big heart and lots of love isn’t easy when you vow to love what’s largely considered unlovable. Bringing darkness into light, and shedding light into the dark, may feel as unbearable as Flannery O’Connor described. But the dedication to doing both quietly and beautifully is a specific ecstasy in which Mirel Wagner excels.

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