The book is about a custody battle involving a seven-year-old girl, Faith White, who may be seeing God.
After the divorce, Mariah becomes deeply depressed, while Faith develops an imaginary friend called her "Guard".
Ian shows up at the Whites' house, where he has a confrontation with Millie Epstein, Faith's grandmother.
Faith performs a few other miracles, including healing a baby with AIDS and showing what appear to be stigmata.
Mariah and Faith flee to Kansas City, where they are confronted by Ian, who is visiting his autistic brother, Michael.