Matthew's newly-found letter states Mary is to be his sole heir and thus gives her management over his share of the estate until their son, George, comes of age.
Lady Edith, who has begun writing a weekly newspaper column and Michael Gregson, a magazine editor, fall in love.
Gregson travels to Germany to seek citizenship there, enabling him to divorce, but is killed by Hitler's Brownshirts during riots.
She places the baby with a couple there, but later reclaims her daughter after arranging for a family on the Downton estate (Mr and Mrs Drewe of Yew Tree Farm), to foster her.
Sampson, a card sharp and previous guest at Downton, steals a letter written by the Prince of Wales to his mistress, Rose's friend Freda Dudley Ward, which, if made public, would create a scandal; the Crawley family connives to retrieve it.