The first alien abduction story on record is that of Barney and Betty Hill, who, in 1961, on a late-night drive, arrived home two hours later than they expected. Disturbed by the missing time, Betty researched UFOs and was soon plagued by dreams in which she and Barney were taken aboard a UFO and experimented upon. Years later, under therapeutic hypnosis, Betty and Barney recounted being taken aboard a ship, experimented upon, and being shown star charts of distant galaxies. As the Hill case was studied, however, several motifs in their report were shown to be linked to publications and movies popular at the time. Sagan, by that time a well-known expert, was invited to meet the Hills. He was taken by their earnestness in regards to what happened, but is more interested in the hypothesis put forward by the couple’s hypnotherapist: that the Hills were not abducted, but instead “had experienced a species of 'dream' together” (104).

Sagan posits that the Hills experienced hallucination. He details psychiatric, chemical, and anthropological studies, which, dating back to 1894, have shown that up to 25 percent of ordinary, functioning adults have experienced a vivid hallucination, that specific chemicals can reliably cause and hinder hallucination, and that the hallucinatory state is common across cultures.