Anna Howe writes to her friend Clarissa Garlow that there is much talk in the world about the skirmish between James Garlow and Sir Robert Lovelace, which ended with the wounding of Clarissa's older brother. Anna asks to tell about what happened, and on behalf of her mother asks for a copy of that part of Grandfather Clarissa’s will, which explains the reasons that prompted the elderly gentleman to refuse his property to Clarissa, and not to his sons or other grandchildren.

Clarissa in response describes in detail what happened, starting her story with how Lovelace got into their house (he was introduced by Lord M. - the uncle of a young Esquire). Everything happened in the absence of the heroine, and she learned about the first visits of Lovelace from her older sister Arabella, who decided that the refined aristocrat had serious views on her. She without hesitation told Clarissa about her plans, until she finally realized that the restraint and silent courtesy of the young man testify to his coldness and the absence of any interest in Arabella. Enthusiasm gave way to open hostility, which his brother willingly supported. It turns out that he always hated Lovelace, envying (as Clariss unmistakably judged) his aristocratic sophistication and ease in communication, which is given by origin, not money. James started a quarrel, and Lovelace only defended himself. The attitude of the Garlow family towards Lovelace changed dramatically, and he was refused home.

From the promised copy attached to Clarissa’s letter, the reader learns that the Garlow family is very wealthy. All three sons of the deceased, including Clarissa’s father, have significant resources - mines, trading capital, etc. Clarissa’s brother is provided with his godmother. Clarissa, who, from childhood, took care of the old gentleman and thereby extended his days, is declared the sole heiress. From subsequent letters you can find out about other points of this will. In particular, upon reaching the age of eighteen Clarissa will be able to dispose of the inherited property at her discretion.

The Garlow family is indignant. One of his father’s brothers, Anthony, even tells his niece (in her reply to her letter) that all of Garlow’s land rights to Clarissa appeared before she was born. Her mother, fulfilling the will of her husband, threatened that the girl would not be able to use her property. All threats were to force Clariss to abandon the inheritance and marry Roger Solms. All of Garlow are well aware of Solms's stinginess, greed and cruelty, since it is no secret that he refused to help his own sister on the grounds that she married without his consent. He did the same cruel thing to his uncle.

Since the Lovelace family has significant influence, Garlow did not immediately break up with him, so as not to spoil relations with Lord M. In any case, Clarissa’s correspondence with Lovelace began at the request of the family (sending one of his relatives abroad, Garlow needed the advice of an experienced traveler) . The young man could not help but fall in love with a lovely sixteen-year-old girl who possessed an excellent syllable and was distinguished by fidelity of judgment (as all members of the Garlow family reasoned, and for some time it seemed to Clarissa herself). Later, from the letters of Lovelace to his friend and confidant John Belford, the reader learns about the true feelings of the young gentleman and how they changed under the influence of the moral qualities of the young girl.

The girl persists in her intention to abandon the marriage with Solms and denies all allegations that she is passionate about Lovelace. The family is very cruelly trying to suppress the obstinacy of Clarissa - her room is searched to find letters that incriminate her, and the trusted maid is driven out. Her attempts to find help from at least one of her many relatives lead to nothing. The Clarissa family easily decided on any pretense to deprive the rebellious daughter of the support of others. In the presence of the priest, they demonstrated family peace and harmony, so that later they could treat the girl even harder. How then Lovelace will write to his friend, Garlow did everything so that the girl responded to his courtship. To this end, he settled near the estate of Garlow under a strange name. In the house, Garlow got an eavesdropper who told him all the details of what was happening there, than he later hit Clarissa. Naturally, the girl did not suspect the true intentions of Lovelace, who chose her as a tool of revenge for the hated Garlow. The girl’s fate was of little interest to him, although some of his judgments and actions allow him to agree with the initial attitude of Clarissa towards him, who tried to judge him fairly and did not succumb to all kinds of rumors and biased attitude towards him.

At the inn where the young gentleman settled, a young girl lived, admiring Lovelace with her youth and naivety. He noticed that she was in love with a neighbor's youth, but there was no hope of marriage for young people, since he was promised a significant amount if he married at the choice of his family. The adorable damsel brought up by her grandmother cannot count on anything. About all this, Lovelace writes to his friend and asks him on arrival to respect the poor thing with respect.

Anna Howe, having learned that Lovelace lives under the same roof with a young lady, warns Clarissa and asks not to get carried away by shameless red tape. Clarissa, however, wants to verify the veracity of the rumors and calls on Anna to speak with her alleged lover. Enthusiastic, Anna tells Clarissa that the rumors are false, that Lovelace not only did not seduce the innocent soul, but, talking with her family, provided the girl with a dowry in the amount of the same hundred guineas that were promised to her groom.

Relatives, seeing that no persuasion and oppression work, tell Clarissa that they will send her to her uncle and Solms will be her only visitor. This means that Clarissa is doomed. The girl reports this to Lovelace, and he invites her to escape. Clarissa is convinced that she should not do so, but, touched by one of Lovelas's letters, decides to tell him about this at a meeting. With great difficulty, reaching the appointed place, since all family members watched her walks in the garden, she meets her faithful (as she thinks) friend. He is trying to overcome her resistance and carries with him to a carriage prepared in advance. He manages to fulfill his plan, since the girl has no doubt that they are being persecuted. She hears a noise behind a garden gate, she sees a fleeing pursuer and instinctively succumbs to the perseverance of her “savior” - Lovelace continues to insist that her departure means marriage to Solms. Only from a letter from Lovelace to his accomplice does the reader know that the alleged pursuer began to break out the lock at Lovelas's agreed signal and chase after the hiding young people so that the unhappy girl would not recognize him and could not suspect a conspiracy.

Clarissa did not immediately understand that the abduction had occurred, since some details of what was happening corresponded to what Lovelas wrote about, offering an escape. They were awaited by two noble relatives of the gentleman, who in fact were his disguised accomplices, who helped him keep the girl locked up in a terrible brothel. Moreover, one of the girls, tired of the errands (they had to rewrite Clarissa's letters so that he knew about the girl’s intentions and her attitude towards him), advises Lovelace to deal with the captive in the same way as he once did with them, which over time and it happened.

But at first, the aristocrat continued to pretend, then making the girl an offer, sometimes forgetting about him, forcing, as she once put it, between hope and doubt, leaving her parents' house, Clarissa was in the grip of a young gentleman, since public opinion was on his side . Since Lovelace believed that the latter circumstance was obvious to the girl, she was completely in his power, and he did not immediately understand his mistake.

In the future, Clarissa and Lovelace describe the same events, but interpreting them differently, and only the reader understands how the heroes are mistaken about the true feelings and intentions of each other.

In his letters to Belford, Lovelace himself describes in detail the reaction of Clarissa to her words and actions. He talks a lot about the relationship between men and women. He assures his friend that, they say, nine out of ten women are to blame for their fall and that, having subjugated a woman once, one can expect humility from her in the future. His letters abound in historical examples and unexpected comparisons. Clarissa’s perseverance annoys him, no tricks affect the girl - she remains indifferent to all the temptations. All advise Clarissa to accept Lovelace's offer and become his wife. The girl is not sure of the sincerity and seriousness of Lovelace's feelings and is in doubt. Then Lovelace decides on violence, after having first drunk Clarissa with a soporific potion. The incident deprives Clarissa of any illusions, but she retains her former firmness and rejects all attempts of Lovelace to atone for the deed. Her attempt to escape from the brothel failed - the police were on the side of Lovelace and the villain Sinclair - the owner of the brothel who helped him. Lovelace finally regains his sight and is terrified of what he has done. But he can’t fix anything.

Clarissa prefers death to marriage to a dishonest man. She sells a little that she has of clothes to buy a coffin. He writes farewell letters, makes a will and quietly fades away.

The testament, touchingly lined with black silk, testifies that Clarissa has forgiven all those who caused her evil. She begins by saying that she always wanted to be buried next to her beloved grandfather, at her feet, but, as fate decreed otherwise, she gives orders to bury her in the parish where she died. She did not forget a single member of her family and those who were kind to her. She also asks not to pursue Lovelace.

In despair, the repentant young man leaves England. From a letter sent to his friend Belford by a French nobleman, it becomes known that the young gentleman met with William Morden. A duel took place, and the mortally wounded Lovelace died in torment with words of redemption.