The story begins with the narrator describing the effects of opium and the fantastical vistas it can inspire. The narrator then tells of his sole experience with opium in which he was accidentally administered an overdose by a doctor during the "year of the plague".

After a disembodied sensation of falling, the narrator finds himself within a strange beautiful room containing exotic furniture, where a pounding sound from outside inspires an inexplicable sense of dread within the narrator. Determined to identify the origin of this sound, the narrator moves towards a window and observes a terrifying scene of fifty-foot waves and seething vortex consuming the shoreline at an incredible rate.