Sir Hallam finds himself at the centre of a national crisis when his friend, the Duke of Kent, asks for help. Meanwhile, storm clouds are gathering within 165 Eaton Place, with Lady Agnes's growing fear over the imminent arrival of her baby, and the servants' concern for Lotte, who refuses to speak. But, as the king finally abdicates, Hallam makes a discovery that will change his life forever.

With no sign of a thaw in relations between Lady Agnes and Maud, Hallam finds his diplomatic skills put to the test at home as well as at work. The servants are intrigued by a mysterious new addition to the household, while a restless Lady Persie embarks on a dangerous flirtation, and is drawn to the thrill of radical politics.

Sir Hallam Holland and his beautiful wife Lady Agnes inherit a dilapidated 165 Eaton Place, and set about restoring the house to its full glory. Former housemaid Rose Buck finds herself back in the house where she was happiest, but the arrival of an unwelcome guest puts a strain on relations, both upstairs and down.