Aldo Sax is an FBI agent specializing in "anomaly theory", a method by which he correlates seemingly unrelated data into a cohesive whole, and currently investigating three seemingly unrelated ritual murder cases around the US. His investigation leads him to a nightclub in Red Hook, where he hears of a drug called Aklo, peddled by a man with a lisp and a veil named Johnny Carcosa. Sax sets up a meet with Carcosa at the dealer's apartment building, where Sax is given a hallucinogenic white powder as a prelude to the Aklo. Carcosa speaks an unknown language to Sax, who experiences visions of spectral planes and hideous primordial creatures, while understanding the truth that Aklo is not a drug, but the language Carcosa spoke to him. The visions, given to him by the Aklo, drive Sax to murder his neighbor using the same Modus Operandi as the murderers he was investigating.