The story centers on a rock band called "HPL" (a very thinly disguised version of the historical band "H.P. Lovecraft") as they get ready to perform at the Fillmore in San Francisco when an iceberg from Antarctica deposits a swarm of shoggoths in the city. The story's primary POV is George, HPL's nominal leader (a thinly disguised George Edwards, the historical founder and lead of the band H.P. Lovecraft), as he and the band go through the day preparing to perform. The story then sees the band's performance interrupted by a shoggoth, which kills a pair of Old Ones attending the concert, as well as noted author and Old One expert Howard Phillips (an analog of H.P. Lovecraft), and the band's panicked efforts to escape the Fillmore.