Jack is the story of Marcellus Friedman (Marc for short), born and raised in Salt Lake City, Utah, as a member of the Mormon church. At an early age he rejected its doctrines and restrictions, much to the dismay of his family. As a promising scientist, he impressed his mentors at the university where he also met Lena, the love of his life. She was the darling of Mormondom that he would eventually make his wife. He was the nonbeliever that her family could never accept. Lena facetiously calls him “Jack,” a mildly disparaging term for inactive members of the church.
Marc never denies the existence of God, though he continues to disdain religion. That begins to change, however, when Franceska glides into his life. Marc considers polygamy a possible solution to his enduring love for Lena and his growing affection for Franceska. Lena’s family and most other Mormons hate the practice, even though their church once embraced it and taught that it was essential for the highest salvation. In the face of universal disapproval, Marc proceeds with stubborn determination. His decision to pursue polygamy wrecks his career, soaks his marriage in grief, and leads him to search his soul, a soul of uncertain existence, for the meaning of life.