The tragic story of love, suspicion and the decent into madness unfolds as Louis and Emily Trevelyan’s marriage disintegrates.
Louis Trevelyan, a handsome, well-connected young man, visits the Mandarin Islands and falls in love with Emily, daughter of the island’s governor Sir Marmaduke Rowley. Although Emily’s upbringing as a beautiful, headstrong girl on a tropical island is a world away from the strict formality of London society to which they return, the couple lead an idyllic life with their infant son and Emily’s sister, Nora.
But their happiness is disturbed by the appearance of Colonel Osborne, an old friend of Emily’s father and a man with a taste for married women. Aware of Osborne’s reputation, Louis tries to warn Emily. When she resists, he forbids her to see him. Angry at being suspected of wrongdoing when she is innocent, Emily continues to meet Osborne, refusing to make any promises to her husband that would imply a stain on her character. Neither side will back down and a gulf begins to grow between them, punctuated by increasingly bitter rows and failed attempts at reconciliation.
Nora is in love with Louis’s friend Hugh Stanmore, who has become a journalist and as a result has been cut off without a penny by his fearsome Aunt Stanbury, who lives in Wells. Nora receives an approach from the rich and charming Charles Glascock, heir to Lord Peterborough. She knows she has no prospect of marrying the penniless Hugh, and that she must marry for money, but she delays a decision.
The rift between Louis and Emily has deepened to the point where a separation becomes inevitable. Louis sends Emily and Nora to live with Hugh’s mother and sister Priscilla at Nuncombe Putney, a small village near Wells. Although initially unsure about living with a disgraced woman, they are soon won over. Meanwhile, Hugh’s younger sister, Dorothy, has been summoned to Wells by Aunt Stanbury, who is looking for a companion in her old age.
Hearing of a male visitor to Nuncombe Putney and assuming it must be Osborne, Aunt Stanbury writes a waspish letter to Priscilla, only to have to apologize when she finds out the visitor was Glascock. He has come to propose to Nora who, somewhat to her dismay, finds herself turning him down. Back in London, tormented by his own suspicions, Louis hires a seedy private detective named Bozzle to keep an eye on Emily. Observed by the diligent Bozzle, a mysterious stranger arrives in Nuncombe Putney. This time it really is Osborne.
A few days later, Nora and Emily are visited by Hugh, who tries unsuccessfully to get Emily to apologize to Louis. Emily sees no grounds for apology — although she did see Osborne, it was at his request and with her sister present. Nora, meanwhile, is upset that Hugh doesn’t declare his love for her during this visit. After having seen off the suspicions of Aunt Stanbury, Priscilla feels that she and her mother have been compromised by Osborne’s visit, and Louis is furious. It’s decided that Emily and Nora will be sent back to London until their parents return, to stay with their uncle, the Reverend Outhouse and his wife in the East End.
Back in Wells, Aunt Stanbury offers Dorothy a dowry to marry Reverend Gibson, a young man whose high opinion of himself is shared by Dorothy’s aunt. Hugh visits the rectory on behalf of Louis and takes advantage of being briefly alone with Nora to propose. Her reaction shows Hugh that she loves him, before they are interrupted by an outraged Mrs. Outhouse, who drives him out of the house.
Louis flees to Italy to seek refuge from his memories. Crossing the Alps by coach, he encounters Glascock and two American sisters – Caroline and Olivia Spalding. In Florence, Glascock falls in love with Caroline Spalding, despite the startling difference in their backgrounds.
Aunt Stanbury throws a dinner party to encourage Gibson to propose to Dorothy, to the dismay of the French sisters, Arabella and Camilla, who are already vying for his attentions. Aunt Stanbury’s heir, Brooke Burgess, has arrived to stay. Dorothy finds him far more congenial than Gibson, and when the Reverend proposes to Dorothy, she declines. Gibson is angry at the rejection, as Aunt Stanbury has assured him of success. He is also aware that he needs to secure a match before the luster of his eligibility wears off. However, he makes the mistake of criticizing Dorothy to her aunt, who promptly throws him out.
Tensions at the Outhouse’s are rising, but Emily is as determined as ever not to admit to any wrongdoing. Osborne, a vain man flattered to be linked to a beautiful young woman, visits the house to enquire after her. Rev. Outhouse turns him away without seeing Emily, but Bozzle, who has been embellishing the evidence of an affair to please his master, nevertheless reports this visit to Louis in Italy. Louis demands that his son be sent to live with him. Gibson has allowed the rumor to spread that it was he who turned down Dorothy, rather than the other way round, and is confronted at the French’s by a furious Aunt Stanbury. He fears his reputation has been ruined, but the wily Mrs. French points out that a proposal of marriage to one of her daughters will lend credence to his story. Cornered, he plumps for the younger and prettier Camilla.
Emily has refused to give up her son, and Louis gives Bozzle the authority to seize him. Prompted by the misgivings of his wife, Bozzle begins to worry that his employer is taking things too far. But he needs the job, so he tries to take the boy from the rectory and fails, thanks to a brave stand by the Rev. Outhouse.
Nora sneaks out of the rectory to meet Hugh, who proposes again. This time she joyfully accepts, although any further action must await the arrival in England of her parents. In Italy, Louis learns of the failure of Bozzle’s mission. He decides to come back to London and reclaim his son himself.