In September of 2004, Dr. Charles Marsh arrived at the Kriegmoor Psychiatric Institute in Bayfield, Wisconsin, anxious to take on his new duties, eager to distance himself from the scandal that had forced him to resign his previous post. Among the patients assigned to Marsh at this time was a young woman named Kari Hansen, a college student who had suffered a nervous collapse during a school-sponsored anthropology dig a year previously. Subsequently, Ms. Hansen began experiencing what hospital records referred to as "a series of vivid hallucinations;" her own words described visions of an "alien" intelligence, a heretofore unknown kind of life form which appeared to her as shadows, often of indeterminate shape, occasionally taking on the form of man. Dr. Marsh came to believe these shadows were real.

Shadows in the Asylum collects, for the first time anywhere, Ms. Hansen's patient records, as well as records belonging to a number of Dr. Marsh's other patients and the related historical evidence that led the doctor to his astonishing conclusions to present a bizarre story of insanity that blurs the line between fact and fiction.