Colonel Fairfax, sentenced to death and imprisoned in the Tower of London, is to be executed on this day. A scoundrel of a relative charged Fairfax with sorcery so as to inherit Fairfax's fortune when he dies unmarried. Fortunately, the Colonel has two good friends in the Tower – the Lieutenant in charge and Sergeant Meryll of the Guards. Meryll's son, Leonard, has just been appointed a Yeoman and Meryll plans to keep him in hiding, free Fairfax, give him Leonard's uniform, and introduce him to the Yeomen as his son.
In the meantime, Fairfax asks the Lieutenant of the Tower to find him a bride and thus foil his relative. The strolling players, Jack Point and Elsie Maynard, arrive and the Lieutenant induces Elsie to accept Fairfax's offer of marriage and 100 crowns. Point is not keen on the idea since he intends to marry Elsie himself – someday, but he consents since she will shortly be widowed. Elsie, desperate for money for her sick mother, is blindfolded and wed to Fairfax. Meanwhile, Meryll's daughter, Phoebe, who loves Fairfax from afar, steals the keys to his cell from Wilfred Shadbolt while flirting with the doltish jailor. Fairfax is shaved and dressed as a Yeoman. Bells toll and the crowd and headsman assemble for Fairfax's execution. The Yeomen sent to fetch the prisoner rush back to report his escape. In a scene of wild confusion, Jack Point despairs and Elsie faints in the disguised Fairfax's arms.
The second act opens with Fairfax still at large. Jack Point, despondent over losing Elsie, plots with Wilfred: if Wilfred will claim to have shot Fairfax, Jack Point will teach him to be a jester. Fairfax, saved from the block, now considers himself a conjugal prisoner with no idea whom he married. Dame Carruthers, housekeeper of the Tower, and her niece, Kate, tell Fairfax that Elsie is married to the escaped prisoner. Fairfax, delighted with his luck, decides to woo his own wife. But as a married woman, Elsie rebuffs him. A shot is heard and Wilfred and Jack Point rush in with their tale of Fairfax's death. Wilfred is hailed as a hero. Fairfax, having heard himself described as being very, very dead, renews his courtship of Elsie under cover of teaching Jack Point how to "woo a fair maid." Elsie, believing herself now a widow, accepts him, leaving Jack Point and Phoebe broken-hearted.
In her misery, Phoebe lets slip to Wilfred her part in Fairfax's escape and has to buy his silence with the promise of her hand. Sergeant Meryll makes the same mistake with Dame Carruthers (who has been pursuing him for years) and pays the same price. The real Leonard Meryll now arrives with Fairfax's reprieve. Fairfax becomes himself and claims Elsie as his wife just as she is to marry the man she knows as Leonard. When she recognizes him as the same person, there is general rejoicing interrupted by the anguished Jack Point. As the crowd sings joyfully to the bride and groom, the jester, spurned by Elsie, falls insensible at their feet.