Loid Forger, the Westalian spy known as Twilight, is handed his hardest assignment yet: get close to Donovan Desmond, the reclusive nationalist politician threatening peace between Westalis and Ostania. The only route in runs through Eden Academy, the elite school Desmond's sons attend, so Loid must present himself as a devoted family man. He adopts Anya, a bright orphan who can secretly read minds, and enters a marriage of convenience with Yor Briar, a mild city hall clerk who moonlights as the assassin called Thorn Princess. Neither spouse suspects the other; only Anya knows everything, and she is too thrilled by the intrigue to tell. Entrance interviews, playground rivalries and a brush with Yor's suspicious brother test the Forgers' fragile act.
Cold war tension simmers between neighbouring Westalis and Ostania. To monitor a dangerous Ostanian politician, Westalis's best undercover operative must fake an ordinary household and place a child in a prestigious private school within a week. The wife and daughter he recruits at short notice are hiding lethal and supernatural secrets of their own, turning a mission built on deception into something uncomfortably close to a real family.