Espers' evocative brew of '60s folk and psychedelia holds a mystique as heavy as misty mountain fog. The Philadelphia band arrived in 2004 with a self-titled debut haunted by labyrinthine acoustic melodies ("Meadow") and glistening autoharp ("Flowery Noontide"), all shaped by Meg Baird's wispy alto and Greg Weeks' smooth harmonies. The follow-up EP The Weed Tree set their time-warped folk to covers of artists like Nico and Blue Öyster Cult; by II and III, the group and their sound expanded, as they dipped deeper into a dark underworld of proggy, Zeppelin-esque rock ("Dead Queen") and soft, eerie pop ("Caroline").