A student in a Parisian boarding-house notices that elderly mute German violist Erich Zann plays strange, desperate music every night with his window shuttered. When the narrator finally peers through that window he sees not the city but absolute, starless darkness — and realises Zann's music is all that holds back what inhabits that void.
One of Lovecraft's own favourite pieces, it exemplifies his doctrine that the most effective horror leaves its threat unnamed and unshown. The conceit of music as a barrier against cosmic intrusion gives the tale a melancholy grandeur.