Epifania Ognisanti di Parerga, the richest woman in England (and possibly Europe), barges into the offices of solicitor Julius Sagamore wanting him to draw out a will leaving everything to her husband Alistair Fitzfassenden (an amateur tennis and boxing champion), and states that after the will is signed, she intends to kill herself.

His bad mood leads to harsh words between the two, and when Blenderbland makes disparaging remarks about Epifania's late father (whom she still worships), she uses her knowledge of and skill at judo to throw him not only all over the room but down the stairs.

As they talk, Epifania becomes extremely interested in the doctor and tells him point-blank that she wants to marry him, She starts to tell him about her father's test, but he interrupts her to inform her that his late mother had made him promise to impose a similar test on any woman who wanted to marry him: he is supposed to give the woman two hundred piastres (approximately thirty shillings or one and a half pounds) and she is to make her living for six months with only that money and the clothes she is currently wearing.

The manager tells them the story about how a newly hired scullery-maid got control of the old inn, upgraded everything and eventually took over, forcing the old owners (his parents) out but giving him a well-paying job and making the business a major success.

Sagamore finally makes Blenderbland see that suing Epifania would be a waste of time; not only will her financial means outlast his, but a jury (presumably all-male) would have no sympathy with a man who had been thrashed by a woman.

With that matter out of the way, Epifania finally decides to divorce Alistair on the grounds of spousal abuse (he had accidentally knocked her out with a solar plexus punch during a fight on their honeymoon) and announces her intention to find a man truly worthy of her.

At that moment, the Egyptian doctor enters, having been summoned to attend Blenderbland, and Epifania announces her intention to marry him, having easily fulfilled the conditions of his mother’s test.

The Millionairess received its world premiere in Siegfried Trebitsch's German translation as Die Millionärin on January 4, 1936 at the Vienna Akademie Theatre with Maria Eis as Epifania.

[5] The Millionairess toured round the UK in the summer of 1940 prior to a planned season in London which was cancelled due to the Blitz.

[11] A well-received production was performed by the American Shaw Festival at Mount Gretna, Pennsylvania July - August 1986 with Jane Roth-Casson as Epifania and Sullivan Brown as The Doctor.

The BBC Sunday Night Theatre broadcast a production on 6 September 1959 starring Dawn Addams as Epifania and Donald Pleasence as The Doctor.