In The Case of the Cryptic Crinoline, Enola Holmes is still living independently in Victorian London when her landlady, Mrs. Tupper, suddenly disappears. Determined to find her, Enola investigates and discovers mysterious coded messages hidden in a crinoline dress.
Her search leads her into a dangerous mystery involving kidnapping, secret identities, and possible links to Florence Nightingale and her brother Sherlock Holmes. Using her intelligence, disguises, and detective skills, Enola follows a trail of clues across London to uncover the truth and rescue Mrs. Tupper.