In order to maintain the state of peace between the rival nations of Westalis and Ostania, a Westalian agent code-named "Twilight" is tasked with spying on Donovan Desmond, leader of the National Unity Party within Ostania. However, due to Desmond being notoriously reclusive, the only way Twilight can get close to him is to enroll a child in the same private school as Desmond's sons and pose as a fellow parent.
To accomplish this and present the image of a happy family, he creates the alias of Loid Forger, adopts a young orphan girl named Anya, and marries a woman named Yor Briar. However, unbeknownst to him Anya can read minds and Yor is in fact a professional assassin. Neither Loid nor Yor are aware of each other's true identities, or that Anya knows their true professions. The family later takes in a dog with precognitive abilities whom they name Bond. Despite these unknown factors and Twilight's occasional lapses of common sense due to years of being a spy, he must learn to play the role of the perfect father and husband in order to carry out his mission.