At sixty-five years old, Antonia is the epitome of a dedicated housewife. But beneath her unassuming exterior lies a peculiar obsession: she finds solace in the privacy of bathrooms, the one place where she can claim effortless solitude with a simple "occupied" sign. Within these walls, she embraces her true calling as a writer, escaping the monotony of her everyday life and forging unexpected connections that will ultimately challenge the amiable facade she presents to the world.

1939. A young art conservator from the Prado Museum is interrogated about a missing painting sought by a colonel. 80 years later, her granddaughter looks for her remains in a pit from the Francoist regime.