J. B. Duff, dyspeptic head of Duff and Trotter, London's classiest provision-merchants, was once in love with a girl called Beatrice, who gave him the air because he could only talk about Duff and Trotter's Paramount hams. Joss Weatherby, second-rate artist and first-rate buzzer, is on Duff's staff, designing advertisements for the hams. He recently did a portrait of the above Beatrice, now Mrs Chavender, widow. The portrait hangs in Claines Hall in Sussex, where Mrs Chavender lives with her rich sister-in-law, Mabel Steptoe, who is married to an ex-pug, small-time Hollywood actor whom she is still trying to civilise, hiring valets to make him dress properly etc. Mrs Chavender's pretty secretary, Sally, is engaged to Lord Holbeton, who sings 'Trees' but can't marry her unless he can get some of the money held in trust for him. And who's his sole trustee? Dyspeptic J.B. Duff, of whom he is much afraid. Sally says she will go and tackle J.B. Duff for him.

Mrs Chavender, revolted by slices of a new ham at breakfast at Claines Hall, learns that it's a Duff and Trotter Paramount, so she goes up to London, with a box of slices, to show Jimmy Duff, her ersewhile courtier, how disgraceful his product is. Joss instantly falls in love with Sally. Duff decides that Joss's painting of Mrs Chavender would make a good advertisement, saying, 'Take this stuff away. Bring me a Paramount ham!' Duff fires Joss, and tells Sally he'll give Lord Holbeton his money if Lord Holbeton will steal that portrait and bring it to him at an inn near the hall where he is going to stay, wearing a false moustache. Sally hires Joss as the new valet for Steptoe. He ('Mugsy') wants to raise enough money to get himself back to Hollywood.

Duff eats sticky cakes and mixes them with brandy and hell breaks loose inside him. So Mrs Chavender cures him (most nice male dyspeptics in Wodehouse are cured by nice women) and love re-burgeons. There is an all-night scrambling of people trying to cut the painting out of its frame in order to get money from Duff. Also two suspects locked in the coal cellar by the butler.

Lord Holbeton gets enough of his money to go to Italy to have his voice trained. Duff rehires Joss, to be head of the Duff and Trotter Art Department. Joss will marry Sally. Mrs Steptoe, loathing English weather (which has ruined her garden party), is happy to go back to California with her husband. Perhaps this is Wodehouse admitting that the weather he has always given England is Californian and here now he is trying to tell the truth.

Source: Richard Usborne. Plum Sauce. A P G Wodehouse Companion.