A Mixture of Frailties takes place in Canada and England during the 1950s. Davies tells the story of a young woman from Salterton, a small city in Ontario, who receives a scholarship to study singing in London. The novel turns on the differences between the provincial world of Salterton and the cosmopolitan world of London.

Monica Gall comes from a lowly background. Her parents are Thirteeners, members of the fundamentalist Thirteenth Apostle Tabernacle. Her father is a union man who has worked all his life at the Glue Works. Monica has a strong sense of family loyalty and has never questioned her parents' beliefs or their position in society, unlike her sister Alice who marries a bank employee and joins the United Church of Canada. Monica has a talent: She can sing, and as a member of the Heart and Hope Gospel Quartet from the Thirteenth...