Victor and Hilary, the Earl and Countess of Rhyall, are struggling to manage their lavish English country estate amidst the twentieth-century inheritance tax turmoil that has hit Britain. To alleviate their financial woes, they have resorted to charging curious visitors a small fee of two shillings and sixpence to explore their grand home. Surprisingly, this unorthodox strategy has become quite profitable, and they also delve into mushroom cultivation for sale while engaging in various entrepreneurial activities related to their estate.

However, their peaceful existence is disrupted by the unexpected arrival of Charles Delacro, a bold American oil magnate who breeches their private space, stripping a “Private” sign off the door. Initially taken aback, Hilary is captivated by Charles’ immense wealth and his brazen demeanor, transforming her initial shock into intrigue. Despite being married to Victor, his confident charm sparks a whirlwind of emotions within her. Their conversation flows easily, leading Hilary to invite Charles for a drink, during which he invites her to join him at the luxurious Savoy hotel in London, his intentions clear but veiled in charm.

When Victor suddenly appears, the dynamic shifts. Observant and knowing, he interacts with Charles in a cordial yet loaded manner. The evening ends with Hilary planning a hair appointment in London, claiming she’ll be spending the night with their single friend, Hattie Durant. Victor, while pretending to be oblivious, offers guidance on train schedules, simmering with jealousy beneath his calm exterior.

The next day, Charles, determined to make his presence known, locates Hilary’s hairdresser and lies in wait outside the salon. The two proceed to his hotel room, crossing further into forbidden territory as they head to the bedroom. Victor, meanwhile, grows increasingly uneasy as Hattie, still pining for him, implores her concerns regarding Hilary’s loyalty. Ignoring Hilary’s wishes, Victor invites Charles to their home under the pretext of rekindling an acquaintance. Charles graciously offers to drive Victor back from London, planting the seeds for future chaos.

As dawn arrives, Victor resolves to maintain a façade of control. Initially, he feigns ignorance about the affair, opting for a fishing trip with Charles instead. In a moment of candor, he reveals that he is fully aware of the betrayal and the threat to his honor weighs heavily on him. Victor challenges Charles, igniting a sense of obligation within the arrogant tycoon to respond. In the dimly lit hallways of their estate, they meet for a duel, firing their weapons once with an eerie silence enveloping them. Victor is left nursing a wound to his arm, while Charles remains unscathed.

Yet, the aftermath reveals a calculated act: both men deliberately aimed to miss, trusting that neither truly wished for the duel to escalate fatally. Unknown to them, the family’s mysterious butler, Sellers, an adept marksman from his past military experience, watched the encounter unfold from the shadows, ensuring that Victor’s hit was not accidental.

This duel’s revelation sends shockwaves among the women in their lives. Hilary wrestles with her feelings, torn between her duty to Victor and her attraction to Delacro. Ultimately, she chooses loyalty to her husband, though her heart remains conflicted. In the interim, Hattie departs with Charles, leaving in her wake an air of uncertainty as this drama of love, loyalty, and rivalry continues to unfold.