Nancy Springer 
Rollercoaster: Enola Holmes Ebook [PDF ebook] 

Meet Enola Holmes. Not only Sherlock Holmes’s sister, but a detective on a mission.Enola wakes on her fourteenth birthday to discover her mother is missing and she is now in the care of her older brothers. Desperate to avoid their attempts to send her to school, she escapes to London, determined to find her mother and rescue her. But will she be able to decode each clue in time? Will she survive alone in London’s dangerous underworld? And will she be able to solve the mystery of the missing marquess before her famous brother?