A series of suicides among high-society matrons coincides with a bizarre jewel theft by a towering Indian who mysteriously disappears when cornered. Kolchak investigates and finds that the Indian is a ""diablero,"" a cursed cliff-dwelling Indian medicine man condemned to walk the earth gathering an eternal horde of jewels. The diablero can change shape into the form of a coyote or crow, and hypnotize anyone with its eyes. Carl must seek the diablero in the highest place he can find, and turn the power of its eyes against it.

A series of apparently unrelated deaths involve each victim being crushed to death, and covered in wet, slimy Spanish Moss. Upon investigation, Kolchak discovers that each victim was related to Paul Langois, a hot-tempered Cajun. However, Langois has an iron-clad alibi: he's been the subject of a sleep experiment and been kept asleep for several weeks. Eventual, Carl realizes that somehow Langois' sleep state has caused him to manifest a subconscious ""boogey-man"" from the Cajun bayou: Peremalfait, a huge creature covered in Spanish Moss that crushes the life right out of you. Peremalfait ""kills"" Langois to prevent him from being woken up, and Kolchak must travel into the sewers of Chicago to kill Peremalfait with the only thing that can destroy it: a spear made out of bayou gum wood.