The book begins with the death of Helen Carey, the much beloved mother of nine-year-old Philip Carey. Philip has a club foot and his father had died a few months before. Now orphaned, he is sent to live with his aunt Louisa and uncle William Carey.
Early chapters relate Philip's experiences at his uncle's vicarage. Aunt Louisa tries to be a mother to Philip, but his uncle takes a cold disposition towards him. Philip's uncle has a vast collection of books, and Philip enjoys reading to find ways to escape his mundane existence. Less than a year later, Philip is sent to a boarding school. His uncle and aunt wish for him to eventually attend Oxford. Philip's disability and sensitive nature make it difficult for him to fit in with the other students. Philip is informed that he could have earned a scholarship for Oxford, which both his uncle and school headmaster see as a wise course, but Philip insists on going to Germany.
In Germany, Philip lives at a boarding house with other foreigners. He enjoys his stay in Germany. Philip's guardians decide to take matters into their own hands and they persuade him to move to London to take up an apprenticeship. He does not fare well there as his co-workers resent him, because they believe he is a "gentleman". He goes on a business trip with one of his managers to Paris and is inspired by the trip to study art in France. In France, Philip attends art classes and makes new friends, including Fanny Price, a poor and determined but talentless art student who does not get along well with people. Fanny Price falls in love with Philip, but he does not know and has no such feelings for her; she subsequently commits suicide.
Philip realizes that he will never be a professional artist. He returns to his uncle's house in England to study medicine and pursue his late father's field. He struggles at medical school and comes across Mildred, who is working as a waitress in a tea shop. He falls desperately in love with her, and they date regularly, although she does not show any affection for him. Mildred tells Philip she is getting married to another man, leaving him heartbroken; Philip subsequently enters into an affair with Norah Nesbit, a kind and sensitive author of penny romance novels. Later Mildred returns, pregnant, and confesses that the man for whom she had abandoned Philip never married her.
Philip breaks off his relationship with Norah and supports Mildred financially, though he can ill afford to do so. To Philip's dismay, after Mildred has her baby she falls in love with his good friend Harry Griffiths, and runs away with him. About a year later, Philip runs into Mildred again and, feeling sympathy for her, takes her in again. Though he no longer loves her, he becomes attached to her baby. When he rejects her advances, she becomes angry with him, destroys most of his belongings, and leaves forever. In shame, and quickly running out of money, Philip leaves the house for good. He meets Mildred once more towards the end of the novel, when she summons him for his medical opinion. As she is probably suffering from syphilis resulting from her work as a prostitute, Philip advises Mildred to give up this life. Mildred declines and exits from the plot, her fate remaining unknown.
While working at a hospital, Philip befriends family man, Thorpe Athelny. Athelny has lived in Toledo, Spain. Enthusiastic about the country, he is translating the works of St. John of the Cross. Meanwhile, Philip invests in mines but is left nearly penniless because of events surrounding the Boer War. Unable to pay his rent, he wanders the streets for several days before the Athelnys take him in and find him a department store job, which he hates. His talent for drawing is discovered and he receives a promotion and a raise in salary, but his time at the store is short-lived. After his uncle William dies, Philip inherits enough money to allow him to finish his medical studies and he finally becomes a licensed doctor. Philip takes on a temporary placement at a hospital with Dr. South, an old, cantankerous physician whose wife is dead and whose daughter has broken off contact with him. However, Dr. South takes a shine to Philip's humour and personable nature, eventually offering Philip a partnership in his medical practice. Although flattered, Philip refuses because of his plans to visit Spain.
He soon goes on a small summer vacation with the Athelnys, hop-picking in the Kent countryside. There he finds that one of Athelny's daughters, Sally, likes him. In a moment of romantic abandon one evening they have sex, and when she thinks she is pregnant, Philip decides to marry Sally and accept Dr. South's offer, instead of traveling the world as he had planned. They meet in the National Gallery where, despite learning that it was a false alarm, Philip becomes engaged to Sally, concluding that "the simplest pattern, that in which a man was born, worked, married, had children, and died, was likewise the most perfect." He stops searching for happiness and decides to be content with his lot.
Output: Why did Mildred end up with syphilis?