The titular character is the little sister of Sherlock Holmes, played in the film by Henry Cavill. Sam Claflin is their brother Mycroft.
The synopsis from Netflix reads: "England, 1884 — a world on the brink of change. On the morning of her 16th birthday, Enola Holmes wakes to find that her mother has disappeared, leaving behind an odd assortment of gifts but no apparent clue as to where she’s gone or why.
"After a free-spirited childhood, Enola suddenly finds herself under the care of her brothers Sherlock and Mycroft, both set on sending her away to a finishing school for ‘proper’ young ladies."
"Refusing to follow their wishes, Enola escapes to search for her mother in London. But when her journey finds her entangled in a mystery surrounding a young runaway Lord (Louis Partridge), Enola becomes a super-sleuth in her own right, outwitting her famous brother as she unravels a conspiracy that threatens to set back the course of history.
The film is "a dynamic new mystery-adventure."
It arrives on Netflix September 23rd.