The omniscient narrator of The Secret Garden begins by enumerating the many defects of Mary Lennox, the ten-year-old girl who is the novel's protagonist. Mary is ugly, with skin made yellow by constant illness. At the outset of the novel, she is living in India with her parents, who have neither time nor affection for her. Her mother, who had never wanted a child at all, has entrusted Mary to the care of a number of Indian servants, whose only instructions are to keep the unloved child out of her mother's sight. Mrs. Lennox is described as a famously beautiful, elegant woman, who does nothing but attend fashionable parties. Though everyone is acquainted with and admires Mrs. Lennox, nearly no one knows that she has a little girl, so totally is the embarrassingly ugly child kept from public view. As the servants are obliged to give Mary whatever she wants (lest her parents be disturbed by her crying), Mary becomes terribly spoiled, selfish, and dictatorial. She loves no one, and no one cares at all for her.
This already unhappy state of affairs is made worse when a cholera epidemic breaks out in the Indian village where the Lennoxes are living. The family does not manage to flee in time to escape the epidemic because Mary's mother, in the spirit of thoughtless egotism that is typical of her, has insisted upon staying to attend a dinner party. On the morning that the cholera finally strikes the Lennox bungalow, Mary's Ayah (the Indian woman who serves as her nanny) does not come to tend to her. Left utterly unsupervised, Mary wanders into the garden and begins to play by herself beneath a tree. There, she overhears a conversation between her mother and a British officer, after which the events of the morning are explained to her. The fact that her Ayah has died of the cholera does not bother Mary at all, as she did not love her nanny or anyone else.
The household is seized by terror and confusion, and in the ensuing chaos Mary is completely forgotten. She shuts herself in her room, and does nothing but cry and sleep for more than a day. When she finally ventures out, the house seems eerily deserted, as though it has been abandoned. Mary drinks a glass of wine left standing on the dining-room table. The wine causes her to fall into a deep sleep that lasts many hours. When she awakes, a small green snake with glittering eyes is the only living creature besides Mary herself left in the bungalow—everyone else, including her parents, has died or fled. A party of British soldiers finds her there and takes the newly-orphaned child away with them.
The first chapter of The Secret Garden goes to great lengths to establish Mary Lennox as a "tyrannical and selfish little pig," who is as ugly as she is hateful: she beats her servants, calls them appalling names, and does not mourn her nanny's death. However, the chapter also lays the blame for Mary's flaws at the feet of her parents, particularly her mother. It thereby introduces one of the novel's central themes: the notion that children must be loved if they are to be capable of loving, and given examples of virtue if they are to be virtuous.
The first chapter also presents Mary as a sickly child. Though the source of her sickness is not entirely clear, the novel subtly attributes it to her childhood in India: "Her face was yellow because she had been born in India and had always been ill in one way or another." India, clearly, is no place for an English child, though the novel suggests that India is at fault, rather than the British invasion of the country.
The relation between health and location and the relation between well-being and beauty are important motifs throughout The Secret Garden. India is presented as a place which breeds illness and ugliness, as both Mary and her father take ill during their time there; though her mother is beautiful, her beauty conceals a moral illness, or an illness of the soul. Illness and its ostensible causes are pivotal to the novel as a whole.