In 1939 London, Miss Guinevere Pettigrew is a middle-aged governess who finds herself once again unfairly dismissed from her job. Without so much as severance pay, Miss Pettigrew realizes that she must--for the first time in two decades--seize the day. This she does, by intercepting an employment assignment outside of her comfort level--as "social secretary." Arriving at a penthouse apartment for the interview, Miss Pettigrew is catapulted into the glamorous world and dizzying social whirl of an American actress and singer, Delysia Lafosse. Within minutes, Miss Pettigrew finds herself swept into a heady high-society milieu--and, within hours, living it up. Taking the "social secretary" designation to heart, she tries to help her new friend Delysia navigate a love life and career, both of which are complicated by the three men in Delysia's orbit; devoted pianist Michael, intimidating nightclub owner Nick, and impressionable junior impresario Phil. Miss Pettigrew herself is blushingly drawn to the gallant Joe, a successful designer who is tenuously engaged to haughty fashion maven Edythe--the one person who senses that the new "social secretary" may be out of her element, and schemes to undermine her. Over the next 24 hours, Guinevere and Delysia will empower each other to discover their romantic destinies.