Convinced that it is no longer in her power to avenge Camille’s death, Mme Raquin decides to commit suicide by starving herself. Thérèse attempts to prevent Mme Raquin’s self-destructive maneuver, yet Laurent is indifferent. In fact, he believes that Mme Raquin’s death could bring a measure of relief. Mme Raquin learns of these sentiments and decides to live after all, because she wishes to witness the fate of her son’s murderers.
Both Thérèse and Laurent consider separating and fleeing. Yet both realize that such a step would arouse suspicions and could bring the law down on them. They stay put in the Passage du Pont-Neuf, along with a new companion: Suzanne. Olivier’s timid young wife begins keeping Thérèse company in the shop, and Thérèse is delighted to have Suzanne’s chatter as a distraction. In fact, because the two women do almost nothing but chatter, their negligence drives away the shop’s last few customers. But Suzanne serves another purpose; because she tends the shop, she allows Thérèse to wander around Paris during the afternoons.
Laurent’s own situation is becoming unbearable. He wanders Paris, crushed with boredom, and returns to the apartment only to beat and harangue Thérèse. (Thanks to one particularly savage beating, the young woman suffers a miscarriage.) His condition is aggravated by vestiges and memories of Camille, including the scar on his neck and the watchful cat François. Driven to the point of murderous annoyance one evening, he grabs Mme Raquin’s tabby cat, swings the creature around and hurls it out the window and against a nearby wall.
Laurent notices that his wife has begun to make frequent disappearances and decides to follow her. Watching from a wine shop, he spots Thérèse, who is dressed provocatively and is casting flirty glances at the men in the street. He follows his wife, sees her fall in with a group of girls and young men who are drinking and smoking, and stalks Thérèse until, in the company of a young man, she disappears into an apartment.
Thérèse’s new activities seem like a good idea to Laurent; by indulging in sensual pleasures, perhaps he too can disregard everything that disturbs him. Later that day, he approaches Thérèse and asks her for 5000 francs. The young woman at first opposes his plan, and even announces her determination to admit her crime to the police rather than give Laurent what he wants. Ultimately, she gives in. And Laurent squanders the 5000 francs on alcohol and women, only to find that these indulgences bring him no comfort.
The violent quarrels begin again. But now, a new state of extreme suspicion sets in. Laurent is convinced that his wife will eventually break down and confess, and Thérèse is convinced that her husband will do exactly the same. They regularly spy on one another. Exhausted and frightened, they resolve to end this state of suffering by committing murder once again. Thérèse sharpens a large kitchen knife, which she plans to use to kill Laurent. Laurent obtains a vial of prussic acid from a friend of his, and he intends to use this poison to kill Thérèse.
Once again the Thursday guests have gathered at Mme Raquin’s, and they are enjoying their best evening yet. Old Michaud and Grivet announce that they never tire of showing up to Mme Raquin’s “Temple of Peace,” to use Grivet’s pet name for the Raquin household. As the guests are leaving, Suzanne notes to Thérèse that she will be at the shop early in the morning. Thérèse - who needs time to complete her murder and flee the premises - tells Suzanne to wait until noon.
The guests leave. Laurent, Thérèse, and Mme Raquin are alone before bed, and Laurent makes Thérèse a glass of sugar water, lacing the drink with prussic acid. Thérèse retrieves her knife from its hiding place. But sensing danger, Thérèse and Laurent turn to face one another at precisely the same time, and discover one another’s murderous plans. Mme Raquin watches in suspense.
The two former lovers burst into tears, feeling pity for one another. Weary and disgusted with their lives, Thérèse drinks half of the poisoned water and Laurent finishes it off. They collapse and Thérèse’s lips come to rest against the scar on Laurent’s neck. Mme Raquin sits over the spectacle, gloating over the murders’ fate for the next twelve hours.
As the final stages of the novel begin, Zola reminds us that Thérèse is still exactly where she was at the novel’s beginning. Images of the grime and shadows in the Passage du Pont-Neuf return with a vengeance, but this time, the settings don’t seem like an unfair punishment for a vital, passionate woman like Thérèse. Instead, these surroundings are all too appropriate for Thérèse and Laurent: “The damp and dirt seemed to have been designed especially for their desolate existence. But they did not dare, they could not escape” (175).
Once more, Thérèse, Laurent, and Mme Raquin attempt new strategies, and once more these strategies fail to bring about any meaningful change. Mme Raquin decides to starve herself, but abandons the attempt; she wants to see “the sinister adventure through to its end” and remains in her role of passive, hateful spectator (175). Thérèse and Laurent both attempt to drown their anxieties in vice, but their efforts have exactly the opposite effect. Laurent, for one, finds that “all he managed to do was to make himself more depressed” (187) and returns to his state of anger and violence.
The irony of this is that Laurent has gotten exactly what he wants out of Camille’s murder - a life of women and laziness, facilitated by 5000 of Mme Raquin’s francs - but is in no state to enjoy what he has obtained. Much the same can be said of Thérèse. In lust and intrigue, she has found activities that are suited to her passionately animalistic instincts. Yet the most she can do is feign passion and joy, putting on the kind of deceptions that she has been putting on her entire life.
Underneath all this vice, however, is a new note of terror and paranoia. As never before, Thérèse and Laurent fear the revelation of their crime; they can no longer trust one another to stay away from the police, and enter what Zola describes as “a state of war” (189). All of this is in stark contrast to the rational way that, earlier, the two accomplices reasoned through their deceptions and mutually agreed upon strategies for misleading Mme Raquin and the Thursday guests. They didn’t like each other any more during these more rational phases, but at least there was a kind of tortured trust, an instinct for self-preservation. Now even that is gone.
The resolution of this escalating animosity is, once more, a kind of ironic wish fulfillment. In their death scene, Thérèse and Laurent achieve many of the things that they had tried, and failed, to achieve earlier in their marriage. They had tried unsuccessfully to endure even the feeling of one another’s skin, but now they are spontaneously driven “into each other’s arms, as weak as children” (193). And as they collapse in death, Thérèse’s lips come to rest against the scar on Laurent’s neck - a gesture that Thérèse had resisted in life, and a gesture that coincides with Laurent’s final moment of peace. Not a happy ending, but one where the unresolved conflicts and loose ends (What will Suzanne think when she discovers all this?) are minimal.