Epifania, played by Sophia Loren, is the world’s richest London heiress, bound by a cruel condition laid out in her late father’s will: she can’t marry unless her chosen husband can turn £500 into £15,000 within three months. When she falls for Alastair, a muscular tennis star, she schemes to win him by putting £500 in stock and then buying it back for £15,000, effectively rigging the test. Alastair, Gary Raymond, finds the arrangement burdensome and soon discovers that life with Epifania is far from peaceful; he is already carrying on with the more domestic Polly Smith, Virginia Vernon.
The heiress’s publicity-stoked romance spirals into melodrama. Epifania’s despair culminates in a self-imposed tragedy on the Thames, but a passing Dr. Kabir, Peter Sellers, a selfless physician who runs an under-equipped clinic for the poor, fails to react to her theatrics. Instead of responding to the danger, he continues with his work, leaving Epifania to misread his indifference as a murder attempt. Julius Sagamore, the family solicitor, then suggests therapy with the noted society psychiatrist Adrian Bland, who himself makes a calculated bid for Epifania’s hand. When Bland dares to criticise her father, Epifania throws him into the river, and Kabir, who dives in to rescue him, becomes the unwitting witness to her latest attempt to ensnare him. Yet Epifania follows, jumping in after him, and their uneasy bond begins to take a fragile shape.
Kabir remains unmoved by wealth, and Epifania’s resolve hardens. She buys the clinic’s surroundings, erects a gleaming new facility, and then proposes marriage as a way to win him. Kabir, feeling the weight of a deathbed promise he crafted to his mother—namely, that he would not marry unless his bride could prove she could take 35 shillings and support herself for three months—appears wary but not defeated. Epifania, ever resourceful, produces the £500 she originally offered and leaves it as a test, confident in her ability to recreate the situation when needed.
To prove her worth, Epifania travels to a sweatshop pasta factory with 35 shillings and confronts Joe, the factory proprietor, Vittorio De Sica. She threatens to reveal workers’ violations unless she is allowed to run the plant. Three months later, she has introduced labor-saving machines, raising productivity and turning the operation into a success. Meanwhile, Kabir struggles to give away his £500. After a gala dinner hosted by a wealthy doctor, Kabir’s former professor and mentor accepts the money on his behalf, a gesture that unsettles Epifania. When Kabir explains that he has already given the money away, Epifania is offended, and she contemplates stepping away from the world of men, even planning to fire her board and retire to a Tibetan monastery while evicting the monks.
Sagamore, sensing the strain behind Epifania’s erratic behavior, visits Kabir at the clinic and warns that her vow to withdraw could be real. With midnight approaching, Epifania seems poised to end the marriage-like bond they have formed. Sagamore then fulfills the will’s terms by purchasing Kabir’s medical papers for £15,000, a move that both protects Epifania’s claim and secures Kabir’s status. Kabir rushes to Epifania, and after a tense moment they share a kiss as he finally confesses his love, signaling a new, uncertain future built on both wealth and genuine connection.
