The Cuckoo (S01E03)

Sir Hallam becomes embroiled in a national emergency when his friend, the Duke of Kent, reaches out for assistance. At the same time, tension rises at 165 Eaton Place, as Lady Agnes grows increasingly anxious about the impending birth of her child, while the staff worry about Lotte, who has fallen silent. As the king's abdication unfolds, Hallam uncovers a revelation that will alter the course of his life in profound ways.