I Capture the Castle is a young adult novel published in 1948 by Dodie Smith. It follows the fictional journal of aspiring author Cassandra Mortmain as she writes about her family’s rise from poverty to wealth through their association with the Cotton brothers. The novel discusses themes of authorship, history, and the multiplicity of feminine identities. I Capture the Castle was adapted for film in 2003 by director Tim Fywell. This summary uses the St. Martin’s Griffin paperback edition published in 1999. 

Plot Summary

Cassandra Mortmain, a 17-year-old aspiring writer, lives with her family in Godsend Castle in Sussex, England. She has begun journaling to practice her speed-writing techniques and learn how to write a novel. Following her mother’s death and her father’s inability to write another novel after his success with Jacob Wrestling, her family lives in poverty. I Capture the Castle begins with the family’s women—Cassandra, her elder sister Rose, and their stepmother Topaz—trying to improve their finances. Rose wants to marry a wealthy man, being largely influenced by the marriage-centered plots of Regency and Victorian English novels to expect such a thing to be possible. Their only income is that which the son of their former housekeeper, Stephen, shares with them, though he is largely motivated to do this by his love for Cassandra.

Their landlord, Mr. Cotton of Scoatney Hall, passes away. The heirs to the estate move to England from America. Simon and Neil Cotton visit the castle unexpectedly one evening and become enamored with the Mortmain family’s strangeness and Rose’s beauty. Simon is an admirer of James Mortmain’s novel; they discuss literary criticism and art, with Mortmain more animated than he has been for years. Rose immediately plans to attract one of the brothers, but her eagerness and affectations drive the Cottons away.

Cassandra’s Aunt Milicent, a socialite in London, passes away and bequeaths her clothes to Cassandra and Rose. They travel to London to pick up the clothes and Milicent’s furs and admire the expensive items in London department stores. Rose becomes even more determined to marry into wealth. That night, on the train home from London and while wearing Milicent’s oversized furs, Rose is mistaken for a bear by the passengers on the platform—including the Cotton brothers. In the confusion, Rose runs into the countryside. Neil finds her, discovers she is not a bear, and the two share a secret kiss. Following this night, the Cottons regularly invite the Mortmains to dinner, picnics, and other outings. Simon falls in love with Rose, who pretends to hate Neil.

During dinner at Scoatney Hall with the Cottons, Cassandra is introduced to the brothers’ English relatives, the Fox-Cottons. Leda Fox-Cotton is a photographer and artist who sees Stephen and immediately wants to make him her model. Cassandra becomes jealous. She is unable to firmly deny Stephen’s affections even though she does not love him. Soon, Simon and Rose become engaged, and the family finds themselves suddenly wealthy.

Rose moves to London with Simon’s mother and Topaz. With Stephen frequently working or modeling and her father behaving irritably, Cassandra spends most of her time keeping up with the castle’s housework. She worries for her father’s mental health but secretly hopes that he has been inspired by the enthusiasm of the Cottons to write again. On Midsummer Eve, Cassandra performs the rites she and Rose usually undertake alone. She is joined by Simon, who is visiting Scoatney Hall for the day. They have dinner at the Hall and dance to his gramophone, during which Simon kisses Cassandra. She realizes that she is in love with him, though she knows he meant little in kissing her because his love for Rose is genuine.

Cassandra grows depressed, is unable to speak with any family member about what happened between herself and Simon, and briefly uses Stephen to assuage her loneliness. When Stephen goes to London again to model for Leda, Cassandra joins him, hoping to confront Rose and figure out whether her sister truly loves Simon. She enjoys an evening with her sister and the Cotton brothers, but Rose admits to not loving Simon. As she still plans to marry him to save the Mortmain family from another period of poverty, Cassandra accuses her of taking advantage of him. She leaves the Cottons’ apartment and spends the night walking through London. She calls Stephen to help her pay for food at a diner, and he asks whether she could learn to love him eventually if they were to marry. Cassandra refuses him.

When Cassandra returns to Godsend Castle, her focus is on her father. She confronts him about his work, discovers that he needs to be shocked into creativity, and initiates a plan to lock him in one of the castle’s towers until he starts writing again. Mortmain is enraged, but after several days, the plan works, and Mortmain begins work on a formalist novel that replicates the emotive experience of creative curiosity. Topaz and Simon unexpectedly show up at the castle, revealing that Rose has left Simon and is missing. They trace a telegram from her to a small seaside town, where Simon and Cassandra discover that she has run away with Neil. It is then that Cassandra realizes Simon will never love her the way he loves Rose, no matter how hard she tries to make him happy.

Rose and Neil move to America so that Neil can start work on a ranch. Mortmain has begun writing again and receives a large advance from multiple publishers. Stephen moves to London permanently to pursue a career in modeling and acting. Simon frequently visits the castle and proposes that Cassandra come with him to America for the winter. Though she still loves him, Cassandra refuses, knowing he still loves Rose. Cassandra finishes her journal with plans to work as an author’s secretary and write a novel.