Episode 2 of The Crown season 4 sets up a truly delicious dramatic scenario: a long, weird weekend at Balmoral Castle during which the royal family is visited not only by Prime Minister Margaret Thatcher (Gillian Anderson), but also by Diana Spencer (Emma Corrin), Prince Charles's new girlfriend and future wife.
The episode is named "The Balmoral Test," a reference to the long-rumored royal initiation which newbies are subjected to at the Queen's estate in Aberdeenshire.