Young Philip Haldane has been living a happy life with his beloved older sister Helen, their parents having died some years previously. But when his sister meets a childhood sweetheart—now a widower—and marries him, Philip is plunged into anger and bitter resentment. He extends this resentment to Lucy, the daughter of Helen’s new husband. Left alone while his sister goes on her honeymoon, he builds a fantastical city out of wooden blocks and household items. Shortly afterwards, he finds himself inside his imaginary city, and is tasked with carrying out a series of heroic deeds.

The Magic City was published in 1910. Like Nesbit’s other children’s books, it was first serialized in The Strand magazine.