The novel is a testimony of an eyewitness who survived the plague epidemic that erupted in 194 … in the city of Oran, a typical French prefecture on the Algerian coast. The narration is conducted on behalf of Dr. Bernard Rie, who led anti-plague activities in the contaminated city.
The plague comes to this city, devoid of vegetation and does not know the singing of birds, unexpectedly. It all starts with the appearance of dead rats on the streets and in the houses. Soon, every day they are collected all over the city by thousands. On the very first day of the invasion of these gloomy harbingers, troubles, not knowing the catastrophe that threatens the city, Dr. Rie sends his long-suffering wife to a mountain sanatorium. To help with the au pair his mother moves to him.
One evening the doctor is summoned to his old patient, a servant of the mayor’s house named Gran, whom the doctor, because of his poverty, heals for free. His neighbor, Kottar, tried to commit suicide. The reason that pushed him to this step, Grano is not clear, but later he drew the doctor’s attention to the neighbor’s strange behavior. After this incident, Kottar begins to show unusual courtesy in communicating with people, although he was previously unsociable. The doctor suspects that Kotthar is unclean, and now he is trying to earn the disposition and love of others.
Gran himself is a man of an elderly, lean physique, timid, with difficulty choosing words to express his thoughts. However, as the doctor later learns, he has been writing a book for many years in his spare time and dreams of composing a truly masterpiece. All these years he polished one single, the first phrase.
At the beginning of the epidemic, Dr. Rie acquainted with journalist Raymond Ramber, who came from France, and a rather young, athletic-looking man with a calm, steadfast gaze of gray eyes named Jean Tarre. Tarr, from the very moment of his arrival in the city, several weeks before the unfolding events, leads a notebook, where he makes his observations of the inhabitants of Oran in the most detailed manner, and then after the development of the epidemic. Subsequently, he becomes a close friend and companion of the doctor and organizes from the volunteers sanitary brigades to fight the epidemic.
Since the announcement of the quarantine, the inhabitants of the city begin to feel themselves, as if in prison. They are forbidden to send letters, swim in the sea, go outside the city guarded by armed guards. The city is gradually ending food, than smugglers use, people like Cotard; the gap widens between the poor who are compelled to drag out beggarly existence, and the wealthy inhabitants of Oran, who allow themselves to buy food on the black market, to luxuriate in cafes and restaurants, to visit entertainment establishments. No one knows how long this horror will last. People live one day.
Ramber, feeling himself in a strange stranger in Oran, is eager to Paris for his wife. First, by official means, and then with the help of Kottar and the smugglers, he tries to break out of the city. Dr. Rie meanwhile works for twenty hours a day, taking care of the sick in the infirmaries. Seeing the dedication of the doctor and Jean Tarre, Ramber, when he has a real opportunity to leave the city, refuses this intention and is adjacent to the health squads of Tarr.
In the midst of an epidemic that takes a huge amount of lives, Kottar remains the only person in the city, contented with the state of things, because he uses the epidemic to make his fortune and not worry that the police will remember him and the trial started over him.
Many people who have returned from special quarantine institutions, lost loved ones, lose their minds and burn their own homes, hoping thus to stop the spread of the epidemic. In the fire in the eyes of indifferent owners rush marauders and plunder everything that they can only carry on themselves.
At first funeral rites are performed while observing all the rules. However, the epidemic takes on such a scale that soon the bodies of the dead have to be thrown into a ditch, the cemetery can no longer accept all the deceased. Then their bodies begin to be taken out of the city, where they burn. Plague rages since the spring. In October, Dr. Castel creates a serum in Oran itself from the virus that captured the city, for this virus is somewhat different from its classical version. To the bubonic plague, the pneumonic plague is added in time.
Serum is decided to be tested on a hopeless patient, the son of the investigator Ogon. Dr. Rie and his friends watch the atony of the child for hours on end. He can not be saved. They are suffering this death, the death of a sinless being. However, with the onset of winter, in early January, there are more and more frequent cases of recovery of patients, so it happens, for example, with Gran. Over time, it becomes obvious that the plague begins to unclench claws and, exhausted, to release the victims from their embrace. The epidemic is declining.
Residents of the city first perceive this event in the most contradictory manner. From a joyful excitement they are discouraged. They still do not fully believe in their salvation. Kottar during this period closely communicates with Dr. Rie and with Tarr, with whom he talks frankly that when the epidemic ends, people will turn their back on him, Kottar. In the diary of Tarr, the last lines, already in illegible handwriting, are dedicated to him. Unexpectedly, Taru gets sick, both types of plague at the same time. The doctor can not save his friend.
One February morning the city, finally declared open, rejoices and celebrates the end of the terrible period. Many, however, feel that they will never be the same. The plague introduced into their character a new feature – some detachment.
One day, Dr. Rie, going to Gran, sees how Kottar shoots passers-by from his window in a state of insanity. Police hardly manage to disarm it. The Gran also renews the writing of the book, the manuscript of which he ordered to burn during his illness.
Dr. Rie, returning home, receives a telegram, which speaks of the death of his wife. He is very hurt, but he realizes that there is no accident in his suffering. The same unceasing pain tormented him for the past few months. Listening to the joyful cries coming from the street, he thinks that any joy is under threat. The microbe of the plague never dies, it is able to doze for decades, and then there may come a day when the plague will awaken the rats again and send them to die in the streets of a happy city.