The Molesley defeat was soon forgotten, as something happened that deeply shocked the Downton residents, upstairs and down: a black man entered the premises. Lady Rose's secret plan for the birthday party was to hire Jack Ross and his band, and now here they were in the kitchen, warming up. On Jack's arrival, Carson almost smashed a teacup in racist surprise. Then he asked, shouting over the sound of a wah-wah trumpet, why Jack didn't visit Africa instead.
Carson was as stiff as a stuffed penguin but he recovered by quoting chapter and verse on the Brits' excellent track record in fighting slavery - “Remember Lord Henley's judgement of 1763?” he said, pointing out that being black in Britain was no longer a flogging offence.
The aristos upstairs struggled rather more. When Lady Rose led the dinner party through to the hall to soak up Jack's insane voodoo rhythms, Lord G initially bridled, fighting hard to quell a racist vomit. He managed a dance, but Edith was frozen to the spot, overcome by racism. “Is it really suitable that Rose has brought this... man here?” she asked the Dowager Countess.
Violet shattered the old posh woman stereotype by being far less racist than the younger members of the family. Not at all, in fact: “Try and let your time in London rub off on you a little more,” she counselled Edith, which was enough for her granddaughter to put down the pith helmet and blunderbuss. Edith can be partially forgiven since her emotions were scrambled by the news that she is pregnant, and that Gregson has not been seen or heard from since his arrival in Munich. Even allowing for a few lost weekends amid the city's eye-watering 1920s nightlife - a spin-off DVD beckons - his disappearance is a worry.
The DC was on roaring form all episode, inveigling Isobel in a curious sleight of hand. Isobel's gardening protege Pegg was still being frozen out, with his alleged lifting of a letter opener now compounded by the news that the Dowager Countess had lost some sort of Japanese trinket. Even an intervention by the DC's permanently terrified batman, Spratt, showing that the ivory doodah had inadvertently rolled into a cleaning bucket, could not sway her from calling Pegg a rotter.
Isobel tried a bit of communist, property-is-theft rhetoric on the Dowager Countess (“Things! Things! Things!”) before turning detective. As the DC's car swept out of the front drive to an appointment, Isobel was lurking in the shrubbery. In she went, conning Spratt by faking a fainting fit and gaining entry to the sitting room, where she Marpled around turning up cushions until she found the knife, rather too conveniently stuffed down the side of a chair.
Confronting the DC with the evidence wasn't quite as satisfying as Isobel hoped, since Pegg had already been re-hired – and had received an apology from the Dowager Countess, the first person to do so since the Queen of Swaziland in 1874 after the notorious “zebra pie incident”. Isobel was dumbstruck. “I'd say that was game, set and match to Lady Grantham,” said Clarkson the reassuringly Scottish doctor, who had arrived so there would be a third person present to say that line.