Doctor Thorne

While Frank and Mary plan their upcoming nuptials, Lady Arabella determines not to give up without a fight. She manages to persuade Mary that marrying Frank would be a selfish act, and that if she truly loves him she should set him free. Meanwhile, Louis is drinking as much as his father ever did, while struggling with his unpopular position in society and Mary's rejection. A troubled and destructive young man, he takes great pleasure in insulting the Greshams when they invite him for dinner.

Sir Roger becomes seriously ill, and Dr Thorne believes that he will die soon. The railway entrepreneur's son pays him a visit, and to the docotr's horror, takes a liking to Mary. Miss Dunstable urges Frank to follow what his heart tells him.

Frank and Mary plan their wedding, but Lady Arabella is still determined to stop them going ahead with the marriage. Sir Roger's son Louis struggles to cope with his new position in society.