The plot of Futakoi Alternative revolves around Rentarō Futaba and his detective agency, which is joined by twin secretaries Sara and Sōju who come to live with him. While the show cannot be specifically classified into one genre, it predominantly embodies characteristics of a romantic comedy. While the initial episodes are light-hearted, the show gradually becomes more serious towards its end. Futakoi Alternative is often criticized for its inability to stay within a single genre, switching between elements of romance, action, science fiction, fantasy, and comedy with almost equal frequency.
