The novel opens with the sisters Ursula and Gudrun Brangwen chatting about marriage one morning at their father’s house in Beldover. Gudrun has recently returned home from art school in London. The two later decide to drop by a local wedding, where they first see Gerald Crich and Rupert Birkin, the two men with whom they will develop affairs that drive the action of the novel. Birkin is a school inspector with extremely unconventional attitudes about life, and Gerald is the heir to the local mining operation that is the central industry of Beldover. Birkin and Gerald hate each other passionately at the beginning of the novel, but after a chance encounter on the way to London they begin to become friends.
Rupert is haunted by his lingering attachment to Hermione Roddice, an aristocratic woman whom he loathes but finds difficult to abandon. Hermione wants to marry Birkin and have him dominate her completely. This situation complicates Birkin’s growing fondness for Ursula, and Hermione and Ursula become enemies. During a weekend gathering at Hermione’s estate, Breadalby, she becomes enraged and smashes a paperweight against the back of Birkin’s head with the intention of killing him. He escapes and considers it the end of their relationship.
Birkin decides to move into a mill house on Willey Water Lake, and Ursula begins visiting him there. The two slowly start to fall in love. One evening, the Crich family hosts their annual public party by the lake, and the Brangwen sisters attend. They meet Gerald and Birkin there and romantic sparks fly, but this is interrupted by the tragic drowning death of Gerald’s sister, Diana Crich, and a young doctor who attempts to rescue her. After the tragedy, Birkin falls ill again and Gerald visits him. He realizes that he loves Gerald, and asks him to exchange a vow of lasting commitment between them. Gerald hesitates to do so although he also loves Birkin.
Gerald’s father Thomas Crich falls ill and is near death. He and Gerald decide to hire Gudrun to tutor Gerald’s youngest sister, Winifred, in art. Gudrun begins visiting their home, Shortlands, nearly every day to teach Winifred. Mr. Crich builds an artist’s studio for Gudrun to use, and she and Gerald grow closer. Meanwhile, Birkin is frustrated with Ursula's indecision and leaves for a vacation in the south of France. Ursula hears nothing for some time, and one evening during a walk sees Birkin in front of his home. They talk and exchange promises of love. The next day Birkin goes to Ursula’s house, intending to propose. He meets her father Tom Brangwen instead, and asks the man for his daughter's hand. Ursula is enraged and refuses him. Birkin stomps away and goes to see Gerald at Shortlands, where the two engage in a violently eroticized wrestling match.
Meanwhile, after a few days Ursula decides she is deeply in love with Birkin and must fight to transform his passion to match hers. Time passes, and one afternoon Birkin surprises Ursula at her school, offering to take her on a car ride. She agrees and he gives her a gift of three rings. This leads to an argument, and Ursula abandons him on the side of the road. Only moments later she returns to make peace, and the two decide to go into town to take tea. Their bond is solidified that night when they sleep together on the ground of Sherwood Forest. Meanwhile, Gerald struggles with his father’s illness, and Mr. Crich finally succumbs to death. Several nights pass, and Gerald finds himself wandering alone night, and eventually makes his way to Gudrun’s house. He sneaks inside and upstairs, and wakes Gudrun up in her bedroom. He spends the night there, asleep while Gudrun watches him.
After a violent argument with her father, Ursula decides to move in with Birkin. The two marry soon thereafter, and Gerald proposes a winter holiday in Europe for the two couples. He talks at length with Ursula and Birkin about the trip, hoping it will be an occasion to develop the romance between him and Gudrun. Gerald and Gudrun leave first, and stop for a night in London where Gudrun meets Gerald’s former mistress Minette Darrington at the Café Pompadour. Ursula and Birkin eventually join Gerald and Gudrun at Innsbruck, a picturesque Austrian retreat town. Things are lovely at first, but soon sour. The group lodges in a small hostel outside of Innsbruck and friction develops between them, in part due to a German artist named Herr Loerke who takes an interest in Gudrun. Ursula begins to loathe the cold and convinces Birkin to leave.
Gerald and Gudrun remain, and Loerke continues to pursue Gudrun. One afternoon she and Loerke are on a picnic that Gerald violently interrupts. Gerald knocks Loerke to the ground and strangles Gudrun nearly to death. He stomps away deeper into the mountains as the sun falls. He freezes to death and his body is brought back to the hostel the next morning by a rescue team. Gudrun sends a telegram to Birkin and Ursula, who return immediately. Birkin is devastated, and the novel ends with him insisting to Ursula that he believes a lasting and intimate bond with Gerald was possible, even while remaining married to Ursula.