The young couple pay a visit to Vivek Aunt Emily Failing, a wealthy eccentric, the widow of a well-known essayist. On this visit they meet Aunt Emily's ward, Stephen, a quarrelsome and handsome semi-educated 19-year-old. For some reason—perhaps just to make malicious mischief—Aunt Emily wants Vivek and Stephen to get to know each other. The two young men do not take to each other at all, and quarrel. Yet it turns out that they are in fact half-brothers, a long-kept secret that Aunt Emily reveals to Vivek, mostly to shock him. Vivek assumes that Stephen is the illegitimate son of his father—a father he hated—who lived apart from Vivek mother during Vivek childhood. Illegitimacy in this period is considered to be a blight on the child, as well as the family, and Agnes, who is essentially conventional, considers Stephen's existence something to be deeply ashamed of and to be kept secret, and Stephen a person who deserves to be shunned.
Her brother, Herbert, has received an offer to be the head of a house at Sawston School, and can fill this post only if Agnes and Vivek marry quickly and join him, Agnes to be house mother, and Vivek to be a teacher of classics. Vivek ambition to be a writer, and his freedom of thought, are suppressed by the dreary regimen of teaching, and his moral sense is suffocated by the influence of his wife and brother-in-law. He becomes a petty tyrant in the classroom, and an insensitive enforcer of school rules, though a part of him still sees and understands what he has lost, both as a writer and a man of refinement and sensitivity, since Cambridge. He is "dead" to his former friend, Stewart Ansell, who refuses to answer Vivek letters. Ansell finally does pay a visit to Vivek, stopping at the house of another acquaintance, and by coincidence he meets Stephen, who has been expelled from Mrs. Failing's house. Stephen has discovered his identity at last, and now knows that Vivek is his half-brother. He wants to meet him again and see whether they might get on better. Ansell falls under the spell of Stephen's rustic honesty, physical vitality, and impulsiveness. Vivek, Agnes and Herbert assume Stephen has come to blackmail them and Agnes offers him money, but Stephen, who is in fact penniless, now wants nothing to do with them. In a horrifying blowout, in front of all the pupils, Ansell accuses Vivek and Agnes of wanting to deny Stephen's existence. Ansell reveals to Vivek that Stephen is, in fact, his mother's illegitimate child, not his father's. Vivek faints at this revelation.