The affably absent-minded Earl of Emsworth, preparing his prize-winning pig for the Shropshire Agricultural Show, is afraid that rival pig-owner Sir Gregory Parsloe is planning to nobble his precious Empress.

Parsloe fears that Emsworth's brother Galahad's memoirs contain scurrilous stories about their younger days in the naughty 1890s - particularly a racy story involving some prawns. He plans to hire private detective Percy Pilbeam to purloin the manuscript.

Emsworth's sister Lady Constance, equally desperate to stop publication, also has a secret plan.

And romance is in the air. His Lordship's new secretary and Emsworth's niece Millicent are secretly in love, but need financial help to pull off the marital merger. Emsworth's nephew, Ronnie Fish, is also in love with an unsuitable person - chorus girl Sue Brown. But Emsworth refuses to allow Ronnie any more money. Ronnie concocts a plan to regain his uncle's approval.