The Case of the Cryptic Crinoline: Enola Holmes 5

Enola Holmes's lonely London days are shaken up when her dear landlady, Mrs. Tupper, is kidnapped! As Enola pursues clues in her search for Mrs. Tupper, she finds that Florence Nightingale and her own brother - Sherlock Holmes - are involved. Soon Enola finds herself jumping out of windows, deciphering a mysterious code, and putting her hidden dagger to use - and she won't rest until poor Mrs. Tupper is safe at home!