Things begin to happen when the Cottons, a wealthy American family, inherit nearby Scoatney and become the Mortmains' new landlords. Stephen, a noble soul, is in love with Cassandra, which she finds touching, but a bit awkward Thomas, a schoolboy, is, like Cassandra, considered 'tolerably bright'.

Stephen, a handsome, loyal, live-in son of the Mortmain's late cook, and Thomas, the youngest Mortmain child, round off the cast of household characters. Cassandra, the younger daughter and the story's narrator, has literary ambitions and spends a lot of time developing her writing talent by 'capturing' everything around her in her journal. Rose, the elder daughter, is a classic English beauty longing for a chance to meet some eligible (and preferably rich) young men. Mortmain's second wife, Topaz, is an exotically beautiful artist's model who enjoys communing with nature, sometimes wearing nothing but hip boots. Ten years before the story begins, he took out a forty-year lease on a dilapidated but beautiful castle, hoping to find either inspiration or isolation there now, his family is selling off the furniture to buy food. The head of the Mortmain family is Cassandra Mortmain's father, a writer suffering from writer's block who has not published anything since his first book, a hit entitled, Jacob Wresstling. The narrator is Cassandra Mortmain, an intelligent 17 year old who tells the story via her personal diaries. This coming-of-age novel recounts in the first person the adventures of an eccentric family, the Mortmains, struggling to live in a decaying English castle during the 1930s. Smith was already an established playwright and later became famous for authoring the children's classic The Hundred and One Dalmatians. I Capture the Castle is Dodie Smith's first novel, written in 1949 while living in USA.

Cassandra i capture the castle