In this sonic fiction, Rosa Arruti aka Nad Spiro reveals an unusual dimension of her work, using just one guitar and four pedals on her sonic explorations through the lost quarries of Montjuïc, the legendary mountain of Barcelona. Armed just with her guitar, Nad Spiro activates subterranean echoes, spectral loops and secret vibrations on an initiation trip through invisible labyrinths. Enigmatically as ever, she invites us to go deep into the sound magma while dedicating each composition to one of the lost pedreres (quarries) of evocative name, hidden nowadays under a different urbanscape.