The novel's protagonist, Iris Chase, and her sister Laura, grow up well-off but motherless in a small town in southern Ontario. As an old woman, Iris recalls the events and relationships of her childhood, youth and middle age, including her unhappy marriage to Toronto businessman Richard Griffen. The book includes a novel within a novel, a roman à clef attributed to Laura but published by Iris. It is about Alex Thomas, a politically radical author of pulp science fiction who has an ambiguous relationship with the sisters. That embedded story itself contains a third tale, the eponymous "Blind Assassin", a science fiction story told by Alex's fictional counterpart to the second novel's protagonist, believed to be Laura's fictional counterpart.