Thomas, a schoolboy, is, like Cassandra, considered "tolerably bright". Things begin to happen when the Cottons, a wealthy American family, inherit nearby Scoatney Hall and become the Mortmains' new landlords. Cassandra and Rose soon become intrigued by the unmarried brothers Simon and Neil Cotton. Neil, who was raised in California by their English father, is a carefree young man who wants to become a rancher in the United States. Simon, who grew up in New England with his mother, is scholarly and serious, and loves the English countryside. Simon is the elder brother and therefore the heir, and is already much wealthier than Neil, so, although Rose is not attracted to him, she decides to marry him if she can, declaring that she would marry the Devil himself to escape poverty. At their first meeting the Cottons are amused and interested by the Mortmains. When they pay a call the very next day, however, the inexperienced Rose flirts openly with Simon and makes herself look ridiculous. Both brothers are repelled by this display and, as they walk away, Cassandra overhears them resolving to drop all acquaintance with the Mortmains. After an amusing episode involving a fur coat, however, all is forgiven and the two families become good friends. Rose decides that she really is taken with Simon, and Cassandra and Topaz scheme to get Simon to propose to her. Simon falls in love with Rose and proposes to her. Rose and Topaz go to London with Mrs Cotton to purchase Rose's wedding trousseau. While everyone else is away Cassandra and Simon spend the evening together, which leads to their kissing. Cassandra becomes obsessed with Simon, but suffers feelings of guilt since he is Rose's fiancé. Cassandra concludes that she must tactfully deflect Stephen's offer of love, and encourage him in his emerging career as a model and a film actor. She joins forces with Thomas to help their father overcome his writer's block by the drastic expedient of imprisoning him in a medieval tower; copes with her own increasing attraction to Simon; and records everything in her journal. Meanwhile, unnoticed by everyone but Stephen, Rose and Neil have been falling in love. To conceal their budding romance they pretend to hate each other. When they eventually elope Simon is left heartbroken, but Cassandra becomes hopeful. Before Simon leaves to go back to the United States, he comes to see Cassandra.