Daughter of an actress, who toured France with an all-female company, playing only Shakespeare's historical plays, Lettice Douffet has inherited both theatricality and eccentricity. Now employed as a tourist guide in a shabby stately home, she attempts to enliven its dull history with her own over-imaginative fantasies, until she is caught in the act and promptly sacked. She retreats to her basement in Earl's Court, where she is visited by the starchy Preservation Trust official who fired her. An unlikely friendship develops as they discover a shared loathing for the carbuncles of modern architecture and the stern, sensible Lottie is drawn into Lettice's attractive world of historical romance.
This almost ends in tears after a nasty accident when the two ladies are re-enacting the execution of Charles I. But, they manage to rise above this minor setback and continue their crusade to "enlarge, enliven and enlighten" with renewed vigour.