Millie Bobby Brown's next big project isn't quite elementary, my dear. It's more high school. Whatever the case, it's a major move in the young actress's career as she's just signed a major deal to not only star in but produce a multi-film mystery franchise. Based on a series of novels by author Nancy Springer, Brown will play Enola Holmes, who just happens to be the much younger sister of famed detective Sherlock Holmes (indeed, the character is 14, the age Brown will turn next month).

In the series, Sherlock is already a famed detective while Enola, 20 years younger, is still at home being raised by their mother. That is until mom suddenly disappears, and it's left to young Enola to solve the mystery. It turns out that she's a gift detective like her older brothers Sherlock and Mycroft (Unlike Sherlock and Mycroft, however, Enola wasn't a part of Sir Arthur Conan Doyle's original stories, but rather an original creation of Springer's). Though, her older brothers would much prefer she continue a traditional upbringing as a proper Victorian-era lady, Enola instead spends a good portion of the books trying to escape her brothers and solve crimes instead. Maybe she'll solve the mystery of why her brother can't chill and just let her live along the way as well.

Brown, of course, broke through with her role as Eleven on Netflix's Stranger Things, but she's fast establishing a big screen career for herself as well. She's already finished shooting her role as the (human) lead in the upcoming Godzilla: King of Monsters, and, according to Deadline, will re-team with that film's studio, Legendary Films, on the Holmes series. Brown will co-produce through her own company PCMA Productions.

While it's somewhat unusual for the stars of the underaged set to have their own production company, it's not unheard of either. Mary-Kate and Ashley Olsen's Dualstar Entertainment Group was in business by the time the twins were just six (today the company still serves as the parent company for the Olsen's many fashion enterprises). Come to think of it, the Olsens also used their company to produce a young girl detective series in their straight-to-video series The Adventures of Mary-Kate & Ashley as well. Though, while the Olsens were solving "The Case of the Fun House Mystery," Brown will be solving things like "The Case of the Cryptic Crinoline."

Brown's Enola Holmes series appears to be slated for the big screen, and could run for several films (there's six novels in the literary series). Here's hoping that it doesn't interfere with Brown's other major goal of starring in a stage musical.

Related: Millie Bobby Brown on the Aftermath of Stranger Things: "My Whole Life Changed"