The story follows Pemrose Lorry, a bright and curious young girl with a keen interest in radio communication—a hobby that was becoming increasingly popular and accessible during the time the novel was written. Pemrose, often called Pem by her friends, becomes fascinated with the possibilities of radio technology and decides to become an amateur radio operator.Through her determination and enthusiasm, Pem acquires the necessary equipment and learns the technical skills needed to build and operate her own radio set. The novel details her journey of self-education and experimentation, highlighting her successes and setbacks along the way.