The title is a word play which is both the name of a kind of flower called "hitorishizuka" and also refers to the female protagonist Shizuka "Shizuka Alone". Based on a book by Honda Tetsuya, Hitori Shizuka follows the story of a girl Ito Shizuka's life from 8 to 31 years old. It comprises 6 mystery stories, each with its own protagonist investigating a murder case. These cases appear to be independent of one another on the surface, but are actually inter-connected by the presence of Shizuka.