When the "Captain Trips" flu epidemic wipes out more than 99% of the population, the remaining few immune to the disease, including Stu Redman, Frannie Goldsmith, and Harold Lauder, set out in search of other survivors, all the while, experiencing visions of the nurturing Mother Abagail and the menacing figure of The Dark Man.

Mother Abagail selects a surprising voice to be her conduit to her chosen Committee in Boulder: the young deaf man Nick Andros. The arrival of a disturbing visitor to the Boulder Free Zone, shakes the Committee and Boulder residents to their core. Elsewhere in the Free Zone, Nadine Cross is haunted by a childhood memory.