Ross is discharged for medical reasons and returns home to find Warleggan occupying the house of his elderly aunt and expecting his first child by Elizabeth.
Elizabeth's son Geoffrey facilitates a romance between Drake Carne and Morwenna while Ross learns that Dwight is a POW in France.
Morwenna's love for Drake causes her to reject an arranged marriage with a pompous minister, and Drake bedevils George by seeding his pond with toads.
Warleggan presses trumped-up charges against Drake in revenge for his romance with Rowenna, and Ross plans a daring rescue of Dwight from a French prison.
Ross and his men successfully return Dwight from France, but Drake is severely wounded, and Watleggan's son develops a serious case of the rickets.
Whitworth becomes sexually frustrated when Behanna asks him to abstain for his wife's health, and Warleggan stands for Parliament after Ross declines the opportunity.
George, newly elected to Parliament, has become obsessed over Valentine's as Whitworth takes on his teenage sister-in-law as mistress.
At George Warleggan's behest, Sid Rouse categorically harasses Drake and his smithy. Meanwhile, Rowella announces to a horrified Rev. Whitworth that she is with child.
Sam consents to wrestle Sid Rouse at the fair in order to get Emma back to church while Warleggan agrees to stop harassing Drake in order to save his marriage.
Caroline goes to London following her child's death, Whitworth reestablishes relations with money, and Ross secretly visits Elizabeth during a Warleggan party.
Whitworth attempts to break off his ongoing affair with Rowella but is seduced into continuing when Solway becomes aware he's being cuckolded.
Warleggan wagers Adderly that he won't be able to seduce Demelza, and when he fails at that, he goads Ross into challenging him to a duel.
Warleggan tries to have Ross arrested after the duel and Elizabeth consults with a doctor to have her baby prematurely to allay George's suspicions.