This Netflix movie is very enjoyable despite its deviations from Sherlock Holmes canon. I've never read the original books by Nancy Springer, but the heroine is very likeable and clever, if a little naive at times. I was afraid that Helena Bonham Carter as the absent mother would be too quirky and wacky, but she was actually quite nice and used in small doses where appropriate. Wikipedia says the mother Eudoria left to live with the Romani, but this movie gives her a more compelling reason to disapear; she's a militant suffragist involved in making bombs, and no doubt thinks her daughter is safer without her.
Enola wakes on her 16th birthday in 1884 to find her mother gone without explanation. Her older brothers Mycroft and Sherlock come to the family estate, shocked to find it rundown, due to Eudoria having lied about upkeep expenses in order to squirrel money away for other purposes. Mycroft resolves to send Enola away to a finishing school, while tasking Sherlock to find their mother. The headmistress is modern enough to have a steampunk car, yet her ideas about women's education remain patriarchal and she even slaps Enola for talking back to her. Enola finds cryptic clues and money left by her mother, so she dresses up as a boy and runs away in the night. While escaping on a train to London, she meets another runaway, a young lord Tewksbury escaping his own family.