The novel opens with the sisters Ursula and Gudrun Brangwenchatting 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.