London, 1978. Hester is stuck; trapped in the same secretarial job for years while her older boyfriend, Julian, refuses to commit. When she’s offered a role working with an exciting film producer, she sees a chance for everything to change. But leaving means breaking her boss’s heart. Then she has a brainwave: tell him she’s leaving to get married. Without thinking, she says her childhood friend Nico is her fiancé. One problem — he knows nothing about it. Soon the two of them are putting on the performance of a lifetime for colleagues, friends, and eventually family. But as the lie spirals out of control, Hester and Nico grow closer, and she starts to wonder: does she really want this engagement to be fake after all?