Young folk musician Billie Marten is slowly but surely carving out a space for herself in an already-crowded field. Her string of singles over the last year — “Heavy Weather,” “Bird,” and, most recently, “Milk & Honey” — point at a tenderness and complexity far befitting her age, and Marten’s latest, the dusty and sentimental “La Lune,” is another solid entry in her small oeuvre. Marten describes the song as “a nostalgic nod to a time last summer where I really badly sunburnt my face, but also about instinctive feelings of being home, without the ‘heat’ of everything.”