Enola Holmes is the creation of American author Nancy Springer who wrote a series of six young adult novels about Sherlock and Mycroft’s teenage sister who becomes a detective in her own right. The lighthearted and enjoyable film adaptation stars “Stranger Things’” Millie Bobby Brown as the titular character in an origin story that is clearly an attempt to start a franchise. Thankfully it isn’t merely a “set-up” film.

We’re introduced to Enola by Enola herself, who breaks the fourth wall and directly addresses the camera and audience to tell us about how her mother raised her after her much older brothers left early. It’s no surprise that the director, Harry Bradbeer, directed almost every episode of “Fleabag,” which relied heavily on this technique as well.

Enola, who tries not to think too much about the significance of the fact that her name backwards spells “Alone,” is clever and spirited and wholly isolated from the world and the social mores of Victorian-era England. She and her mother (a lovely Helena Bonham-Carter) who are fiercely independent except from each other, use their stately mansion as a playground. They practice archery and tennis indoors, blow things up in the name of science, read books and generally don’t seem all that concerned with the upkeep of anything but their minds.