Sir Harcourt Courtly is lured away from the epicentre of fashionable London by the promise of a rich and beautiful bride, Grace, several decades his junior. Arriving at Oak Hall, Gloucestershire, he marvels at this rural Venus until her charms are eclipsed by her hearty cousin, the foxhunting Lady Gay Spanker. Meanwhile his disguised son turns up in flight from his creditors and falls head over heels for Grace. When Lady Spanker discovers the young couple, she needs little prompting from the visiting chancer Dazzle to lead Sir Harcourt astray.

Dion Boucicault, the Irish genius of London theatre in the age of Dickens, wrote the brilliantly funny London Assurance in 1841 and thereby created - in Sir Harcourt and Lady Spanker - two of the great comic roles of the English stage, played at the NT by Simon Russell Beale and Fiona Shaw.