David Mitchell and Gemma Whelan star in a two-hander Christmas special, in which Will and Kate find themselves spending Christmas in lockdown far from their families as the plague ravages London. Kate fills her days in isolation with an endless series of projects, Will has more pressing concerns - with James I now on the throne, he needs to come up with a masterpiece to retain favour at the royal court and avoid execution. But while he may have time on his hands to write, inspiration is in very short supply