London Assurance

Act 1
Charles and Dazzle arrive back at Sir Harcourt's London home after a night on the town, and manage to avoid Sir Harcourt with Cool's help—Sir Harcourt still believes Charles is a clean-living innocent. Max arrives to make the final arrangements for Sir Harcourt's marriage to Max's niece Grace—by arrangement, Sir Harcourt has financially helped Max in return for making Grace's inheritance contingent on her marrying Sir Harcourt (if she does not, it will pass to Charles). Sir Harcourt leaves and Dazzle bumps into Max, gaining himself an invitation to Oak Hall, Max's country house—a trip on which Charles will accompany him.
[edit]Act 2
At Oak Hall, Grace explains to her maid Pert her acceptance of marriage to the aged Sir Harcourt and her view of love as an "epidemic madness". Charles and Dazzle arrive, and the former (not knowing of his father's marriage plans) immediately starts courting Grace. When his father arrives, Charles pretends, in the face of all evidence, that he is a man called Augustus Hamilton who merely bears a remarkable likeness to Charles and convinces his father for a time.
[edit]Act 3
Lady Gay Spanker and her husband "Dolly" arrive, and Sir Harcourt immediately falls in love with the former. Grace begins to fall in love with Charles/Augustus in spite of herself. When Lady Gay interrupts their courtship, Charles easily persuades the lady to distract Sir Harcourt from marriage to Grace by apparently accepting his affections.
[edit]Act 4
Charles leaves as 'Augustus', returning as Charles to tell Grace that 'Augustus' has been killed, to see if she really loves him, whilst Lady Gay and Sir Harcourt plan to elope together.
[edit]Act 5
The elopement is frustrated by Max, Dolly and the local lawyer Meddle. Dolly challenges Sir Harcourt to a duel. Sir Harcourt realises he has been duped and resolves to release Grace from their marriage contract.
[edit]Act 6
Max prevents the duel and Grace insists on going through with the marriage to Sir Harcourt, as a ruse to force Charles's hand. Charles's creditors catch up with him. Dolly forgives Gay and Sir Harcourt finds out his son's true nature as well as acceding to Charles's marriage to Grace.