Connie travels to Venice by way of London, Paris, and the overland route through the Alps. She finds herself awakened to sensuality in peoples' bodies, noticing how few people have truly alert bodies, and how few places have any appreciation of sensuality. She longs to be back in Wragby, away from the cloud of tourists bent single-mindedly on enjoying themselves. In Venice, she and Hilda join her father, Sir Malcolm and several others, including Duncan Forbes, as guests in the home of a rich Scotsman, Sir Alexander. Connie has a pleasant but not fabulous time in Venice, bathing with Hilda on remote beaches across the lagoon, ferried by the gondoliers Daniele and Giovanni.
Soon, however, she gets letters from Clifford and Mrs. Bolton, telling her that Bertha Coutts, Mellors' wife, has come back to him. He expelled her from the house, but she broke in again, and he has gone to live with his mother, abandoning the house to Bertha. Bertha apparently found perfume in the house, and the postman also recalls hearing a woman with Mellors one morning; they do not, of course, know that this woman was Connie, but Mellors is suspected of adultery, and Bertha is spreading rumors accusing him of sexual deviancy. Connie's first reaction is a revulsion against Mellors. She feels humiliated to be associated with a commoner like him, with somebody who would marry Bertha Coutts. But she comes around, remembering his tenderness to her and how he awakened her sexually. She sends a note of support to Mellors through Mrs. Bolton. With a second letter from Clifford, and one from Mellors, Connie learns that the situation has gotten worse. Bertha Coutts has begun to spread the rumor that Connie herself was Mellors' paramour. Coutts has been silenced by an injunction from Clifford. When Clifford confronted Mellors with questions about his sexual conduct, Mellors responded disrespectfully; Clifford then fired Mellors, who went to London. Meanwhile, Connie is now certain that she is going to bear Mellors' child.
Connie and her family return to London, where she meets up with a dejected Mellors. Mellors says that they should call their relationship off: he has nothing to offer her, and he is too proud to live on her money, as a consort to an aristocrat. But they go back to her room and make love, and she tells him that she admires the courage of his tenderness, his ability to ignore shame and appreciate the physical. She urges him to trust the tenderness between them, and to disregard the worldly differences. He agrees to stay with her, and even to love their child, despite his fears about the future of society.
Connie discusses her situation with her father, who, despite his happiness that she has found sexual satisfaction, is outraged that her lover is a commoner. But Sir Malcolm agrees to meet Mellors, and they get along well, discussing sex earthily: they have a common ground in sensuality. Between Hilda--who still hates Mellors--Connie, Sir Malcolm, and Mellors, they develop a plan. Mellors will lay low and pursue his divorce with Bertha. Connie will pretend that she is having an affair with Duncan Forbes, who will be named as the father of the child and the co-respondent in the divorce (if Mellors is named as father, his admission of adultery will complicate his own divorce). Clifford is more likely to accept Connie's having an affair with Duncan, a member of the leisured class, than with Mellors, a gamekeeper. Duncan agrees to pose as the father, despite Mellors' insulting his art by calling it soulless and self-indulgent.
Connie sends Clifford a letter, telling him that she loves Duncan, and asking for a divorce. Clifford, despite having inwardly anticipated this, goes into shock. Mrs. Bolton comforts him and tends to hi; more than ever, he becomes like a child in her arms. They enter into a perverse relationship, both sexual and parental. She cares for him, and even loves him, but also despises him for his weakness. Clifford refuses to divorce Connie, demanding that she come to Wragby. She does come, and in a confrontation is forced to admit that her paramour is not Duncan but Mellors. Clifford is outraged, and, furious, accuses her of depravity; he continues to refuse to divorce her. She leaves Wragby, and goes with Hilda to Scotland. Mellors, meanwhile, works on a farm, making money and waiting out the six-month divorce proceedings.
The novel ends with a letter sent from Mellors to Connie, summing up the message of the novel about the social blight upon England. The masses of men are emasculated, poor, hopeless, devoted only to getting and spending money. Without a radical change, the future is bleak. Only with a mass transformation, a realization of the power of sensuality, will people restore humanity and joy to their lives. Mellors comforts himself with thoughts of Connie, and the passion that exists between them: "we fucked a flame into being."