Thérèse Raquin is a story of the consequences faced by the lovers Thérèse and Laurent who murder Thérèse's husband Camille. The lovers conceal their crime and manage to escape the justice system, but find their own punishment in the course of their terrible marriage.

Thérèse comes to live with her sickly cousin Camille as a small child. His mother, Madame Raquin, subjects Thérèse to the same treatments as her precious son. When they are old enough, Thérèse and Camille marry. Camille insists that they move to the city. Madame Raquin purchases a dilapidated shop for her children in a disreputable part of town. Thérèse is resigned to her dull life with her disgusting husband. Camille finds a job and Madame Raquin helps Thérèse run the shop. On Thursdays, Madame Raquin entertains a few friends. Laurent, a childhood friend to the couple, starts visiting the family regularly. Laurent kisses Thérèse the first chance he gets alone with her, beginning a passionate love affair. To be together, Laurent takes time off work, and Thérèse pretends to have headaches to give her leave from the store. Their affair continues for months, until Laurent risks losing his job if he takes off any more time from work. Thérèse visits his tiny room one evening. They long for Camille to be gone so that they can be together. Laurent decides to kill Camille.

Thérèse, Camille, and Laurent take an outing where Laurent throws Camille from a boat. The party that rescues Thérèse and Laurent backs up the cover story for the police report. Laurent gets Madame Raquin's friend Michaud, a retired police commissioner, to help break the news of her son's death. When Camille's body arrives at the morgue, Laurent buries the crime along with the body. The lovers do not meet again, wanting to wait until they can be together openly. The Thursday gatherings continue. When Thérèse's mourning period is over, the couple succeeds in getting Madame Raquin to suggest that they marry. When Laurent's father refuses to give him any money, Madame Raquin signs her life savings over to her niece.

Starting with the wedding night, Thérèse and Laurent have a horrible marriage. The corpse of Camille seems to come between them. At first, they cannot stand to touch each other, but later, they try to drive away their horror with passion. Nothing eases their guilt. Madame Raquin becomes speechless and paralyzed, unaware her "children" are her son's murderers. However, she finds their crime out, but is unable to report them. Thérèse and Laurent have a violent marriage with no love, although the continuing Thursday friends never suspect their unhappiness. Finally, Thérèse and Laurent decide to kill each other. When each sees what the other plans, they drink the poison Laurent has planned to use on Thérèse. They both die, as Madame Raquin watches their punishment.