Nearly every music genre has an avant-garde wing, an "underground" scene escaping the notice of mainstream press. Hip-hop is no exception. San Francisco duo Blue Sky Black Death — Young God and Kingston — got together with vocalist Yes Alexander and the result, Slow Burning Lights, redefines what a hip-hop disc is "supposed" to sound like. There is no rapper/MC — all vocals are by Alexander, whose forlorn, little-girl-lost voice recalls Mazzy Star's Hope Sandoval and Cocteau Twins' Elizabeth Fraser. The production is almost dub-like as Alexander coolly coos the melody and spare instrumental (keys, guitar, saxophone) motifs fade in and out while languorous, maximum-chilled beats anchor the songs. The overall ambiance of Lights recalls Brian Eno's song craft circa Another Green World and Before and After Science, while the somber cadence of Alexander's vocals occasionally evokes sacred music from the Middle Ages (think Anonymous 4, Hildegard von Bingen, and the ancient works that inspired Dead Can Dance). Warm, gauzy, and inviting, Slow Burning Lights is a florid sonic maze to willingly get (and stay) lost within.