The year 1937 finds Maisie, reeling from recent personal tragedies. The happiest period of her life has ended abruptly and after a period of time seeking solace in America and India, she decides to return home. But as her ship sails closer to England, she is overcome with fear that she is still not ready to take up her past life. She disembarks in Gibraltar, ignoring an ominous warning from the ship's captain. Gibraltar is perilous - this key British stronghold is a hub of clandestine activity, overrun with intelligence operatives, double agents, and refugees fleeing the Spanish Civil War just across the border.