It's the 1930s and a mysterious illness is spreading over Scotland. But the noble and ancient family of Inverkillen, residents of Loch Down Abbey, are much more concerned with dwindling toilet roll supplies and who will look after the children now that Nanny has regretfully (and most inconveniently) departed this life...

Loch Down Abbey is full of guests for a Highland Ball. Including several uninvited members of the Inverkillen clan, the Abbey's former residents. Housekeeper Mrs MacBain thinks her biggest challenge will be finding suitable rooms for everyone and keeping the peace at cocktail hour.